He's not bad, but I probably wouldn't go crazy burning crystals to gear him up or anything. He does best in really long fights where his offense can ramp up, which pretty much means raids. I use him to solo HAAT (the whole thing), but he's probably not worth gearing just for that since there are several teams that can do it now.
I have also used him in 3v3 GA under Jango (just for the extra speed, really) to 2-man weaker teams. For regular GA I run the full Prepared team on defense (Qira/Young Han/Young Lando/L3/Vandor) and while it's not exactly a total pushover, I don't see it put up successful defenses very often. The only zeta is Vandor, so I guess it might do a bit better with zetas on Qira and Young Han, but I would say overall he's a "nice to have" character at best.