You should probably wait until you get some higher level Eevees to start powering up your Eeveelutions. 1711 is high, yes, but when you get to level 30, they will start to become 2000+. My advice is to wait until then to power them up. If you can't wait that long, power up your strongest one or you'll probably run out of Stardust or end up with a weaker CP Pokémon.
Which Vaporeon?
Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Is any of these Vaporeons worth powering up? The middle one (1588) has Hydro Pump and the other two have Aqua Tail. Check the image for all their info.

Answers
The middle one is not bad... of course, you could always wait until you get a better one, but that might not come as soon as you'd want. If you have the dust and candy to spare, then powering up the middle one is not a bad idea ( I use a single ~2k CP Vaporeon with Gun + Tail for virtually everything... this is from when Tail was better than Pump... the mon is roughly 85% IV, but it means nothing... I beat entire gyms with that single Vaporeon in a single go... dodging is king ).