Tech Rank up

Dexman1349

I'm almost ready to R5 another 4* tech and am seriously debating who to rank up (if I rank any at all).

Current list of available champs (unduped unless noted otherwise):
Howard (sig 40)
Stark Spidey
Starlord (sig 99)
Yondu
Nebula
Ultron
Ironman (sig 20)
Warmachine (sig 20)
5* Hulkbuster

I have Vision at R5 already, so no real need for immunity but he doesn't hit very hard and I don't use him unless I need to (AW attack).

Thoughts so far:

• Howard is fun to play with but not worth R5 with the other options available
• Spark gets a ton of rave reviews, but I actually ranked him down because I didn't like him and needed a immunity champ (this was before I pulled Nebula).
• Starlord is the obvious choice for many but the R4 version seems to be strong enough, and combine that with the fact that so few fights get to significant hit streaks and that I have all the other good options makes me hesitate.
• Yondu has great utility on both attack and war defense. I hesitate on him because the rest of my R5 team is bleed heavy.
• Nebula is an intriguing option. Love her immunities and she seems to hit hard.
• Ultron isn't a horrible choice. He would just be another Vision but have regen instead of power control.
• Ironman and Warmachine are on the list simply because I have them.

Or do I just save my cats for later? I only have a 5* Hulkbuster and I'm not spending anything on him unless I have a gun to my head.