5* Viability

famousfoxking

What is the general consensus on 5* feasibility these days, when does it become worthwhile to level & use them?

I currently have
2/0/1 Phoenix
0/2/1 Silver Surfer
2/0/1 Old Man Logan
0/1/1 Green Goblin
0/1/1 Spider-Man Black
1/0/0 First Avenger
0/0/0 Iron Man 46

All unleveled. I play PvP primarily, as PvE is not at all worth the effort. I'm on day 922, so despite the relative weakness of my roster, I regularly see 400+ 5* characters once I'm past about 600 in PvP. Had I even a single yellow OML cover, I'd probably dump ISO into him, but i'm dubious about his effectiveness at his current cover state.

Is Phoenix worth bringing up to 300? Is GG worth bringing to 285? I've been using the goblin in Nefarious foes and he's entertaining but SLOOOOOOOOW. Spider-man doesn't seem worthwhile with only a 14AP power. Surfer is basically in the same state as OML: I don't have the marquee power that would make him viable.