As far as my knowledge goes, more scripts and plug-ins are actively being made by fans. The developers have moved on to MV.
Even if you weren't making a Pokemon game, from a coding standpoint of actual development, you need an IDE to mess around with the engine. It's really unattractive to me when the programming language switches over to JavaScript and accessing means to view the engine and tweak becomes a hurdle.
MV does look appealing on a service level, but most of things they offer are already plugins for both XP and VX Ace. Hell, Visual Battles does so much more than sideview battles and it was made as a plug-in-play script.
Graphics-wise, MV is better on that department, but it's nothing that a few scripts hasn't already done.
If you want MV and it looks appealing to you, I'd get it. But as someone who's fiddled around with the RPG Maker for a few years, it's not worth the 70 dollar price tag.