DW NEXT delivery isn't until Monday from Amazon. Wonder if I should just get it earlier from eBay. 
UMvC3 is a fun fighting game with a pretty low learning curve. If you have any interest in the characters or fighting games, it's a great game and an excellent port on the Vita. If you don't plan on going online with it though, I'd not recommend it as a purely offline game; it's very lacking in single player content.
No idea on VT4 but it looks great and seems like it'd be fun as well.

I wanted to buy either Virtual Tennis 4 or UMVC3 really badly but I decided to hold off because I want NG Sigma Plus.
My next purchase will be either VT4 or UMVC3, I've never been big into either of those games, not because I don't like them but rather because I never buy them. Any advice on either of em?
UMvC3 is a fun fighting game with a pretty low learning curve. If you have any interest in the characters or fighting games, it's a great game and an excellent port on the Vita. If you don't plan on going online with it though, I'd not recommend it as a purely offline game; it's very lacking in single player content.
No idea on VT4 but it looks great and seems like it'd be fun as well.