Me personally, I'd look into MV since it has more plugin support. I've even had some coders I know whip up some crafty plugins for MV (clicking pictures, image collision, etc). I can't really speak for MZ, but I've read that it's newer software, and has a lot of easier interfaces than MV, but both of them have all the essential features for an RPG, both have scripts, and both have plugin support. But as I said I prefer MV just because I have a folder with over a hundred plugins, and I've been using it for years so I could probably answer any question you have with it.
However I suggest you do some research and choose the one which has the support and plugins your type of game would need.