It comes down to user preferences, more than all else.
VX does simplify some of the processes that XP and previous iteration had, such as doors, inns, and a few others. For example, making a door in XP required you to set both transferring events, but in VX you only need to create one of the transferring events because the other end is handled by the editor. Another simplified feature is the creation of the World Map. Though the feature was available in RM2003, it was missing in XP, so VX only brought it back by including the tiles required. Faces have been implemented as a default feature, but was possible in XP thru Scripting. The Scripting Engine from some coders perspectives seems to be better and more optimized.
The Default Material in VX really depends on the taste of the creator. The Default Battle System for me was a disappointment, as was XP's DBS, but VX's by default has no battle background, and has to be implemented through scripting. The default battle system though better coded was a step behind XP's design wise. The art direction also depends on the user, it wasn't bad, but I prefer the style used by XP, but you can swap out and change the graphics for you project.
The way you handle graphics also depends on the user, if you use only default(RTP) art/sprites or download other peoples work, there isn't much noticeable different in Usage. But if you make your own graphic you may prefer XP's way of handling(sprite layout and such) over VX's, or the other way around. If I were to create my own tilesets/character sprites, I would prefer XPs method over VX because it feels alot more simple.
Mapping in XP you had to work the layers yourself, in VX the layers are handled thru the tilesets it seems. Again this is a user preference.
Final Word, I can't really tell you to get either VX or XP, so I suggest you download both trials and play around with both for the 30 day period, and decide based on your reactions.
VX is good, but I prefer XP