Blissey or Lugia as potion efficient generalist attacker

I used Blisseys quite a bit, and I have tried out my dt/fs Lugia a bit. Lugia is certainly more bareable than Blissey and fs with STAB does a nice chunk of damage. It is pretty comparable to my lick/bs Snorlax.

However, with the overall weakness of gyms Dragonite just makes more sense.

Edit: As far as being potion efficient, it doesn't really matter. If you happen to face a fully motivated pokemon, they only have the high cp for the first fight. I don't even use potions on my gym attackers, only revives. Dragonites, Tyranitar, and Vaporeon at half health are more than good enough.

Maxed a 98iv Lugia for gym attacking (and as a trophy), no regrets. Saving tons of potions and sky attack is fun to play with. 95iv or below i would have not invested. Cant really answer your question but for me it was worth it.

Once I get to probably 400+ rare candies, I'll start powering up to Level 30 some legendaries too...Up to 160+ rare candies now and until Mewtwo comes out (safest bet), I'm going to put some in my 91% Lugia since it's IVs are at least over 90%...

Gyms are just too easy to build any mon for gym attack. I am also tempted to max out my Blisseys just to annoy and troll people in the area since I don't have any good candidates to use stardust on...