Well, isn't the Evo 3D only available to Sprint (or whatever the Evo line is on)? It'd depend how much you want to switch carriers. The Thunderbolt's a pretty good phone, I think, but it's the only smart phone I've ever had, so maybe that kind of "disqualifies" my opinion.
I'm sure the new Evo will technically be better, in terms of specs, and of course, the 3D stuff. Personally, I'm not sure I see much point in 3D on a phone. I mean, I get why it's neat for movies, or gaming, but aside from those things, how practical could it really be for a phone? I dunno, maybe that's just me.