Which unorthodox pokemon is worth powering up?

Im looking for a good ivs C/CC Heracross for a long time. I caught lots of them but only crap ivs. This mon is rated 9/10 and have the same attack and more defense than Machamp, only less HP. I would power it up to level 30.

An advantage of powering up ursaring in favor of heracross would be having a neutral typing that, while not dealing STAB (1.2x), is not weak to Snorlax and eventually blissey's psychic and fairy attack(s) [snorlax: ZHB, Blissey: ZHB, Psychic, DG]. This of course is when blissey is released as a raid boss

If you're lacking larvitar candy houndoom can be great against
Gengar and alakazam. It does take only 1.4x damage from SE where as Tyranitar is 1.4^2x, which is helpful if either zam or gengar are running focus blast, although it should probably not take a hit either

Just from personal experience, Ursaring. He's a counter-counter. Works well against ZH Snorlax and Blissey too unlike the others.

I've powered up a 93% S/Fp Houndoom to level 30...Don't own a Tyranitar yet and there are very few dark type attackers out there so I'd vote for Houndoom...

Tyranitar is better, but I haven't found one yet so I'd say Houndoom for variety and general use...

I've been evolving high level Houndooms like mad and keep getting Fire/Dark or Dark/Fire moves...insane...(shows I've caught 27 in my dex)...

There's no way to answer such vague questions anymore.

Are you looking to improve a certain raid crew? Do you have a ton of dust? Do you not have or cannot obtain the more optimal version of these mons through raids?

What are you trying to achieve?

i've powered up each one of the pokemon mentioned in your post

86% Heracross, C/CC, catch at lvl 25 and had no fighting Champ or Wrath(i'm brazilian)
97% Houndoom, S/FP, i've lost 3 ttars, getting desperate here
97% Ursaring, C/CC, same as Hera
91% Cloyster, IS/A, i have only 1 good ice lapras
all to lvl 30 no regrets.
All before gym rework and raids be a thing