Purchasing VIP will reward you with:
Aqua name
Particle effects
A CraftyCrate - contains random goodies and resources!
Access to the VIP+ Only Lounge
VIP+ Hats
VIP+ PVP Arena
VIP+ Parkour
VIP+ Elytra Area
Access to the VIP Lounge
The VIP Crafting Guild
Private TP request
Random Teleporter distance extended to 15k
VIP warps to various locations
Free second Set Home
Access to third Set Home

That's copied straight from the store. But I don't know how to access much of it.