Invulns, been done to death, you'll disappear amongst many Invulns and can only wonder what sets you apart. Bio anything not so much. How do you entertain yourself, how to you keep yourself interested, don't be just another, take that Bio and go tank Ghost Widow for 15 mins without outside assistance with a lvl 50 SO build. You can find anything you want, achieve what you want if you look in all the right places. Invulns, ya trip over them ingame, they're common, they separate themselves by tiny build changes, playstyle etc.
When you tank, can you tank for any team make up, or will you rely on certain people, certain powersets to get by, there is no trinity in this game, you can eliminate need for suck it and see. The game can be more than a farm, more than a keymash it can be whatever you want it to be and imo Bio well it may have one or two firsts to do whereas other invulns have been there and done that.
That's said I wouldn't do safe myself and would do every powerset ingame with relentless altitis.