Retail is better because it has Fx lights, which could make a build look really improved if you go to a dark map and you can get the lighting just right.
It is also better because it is more stable, and it has
crappy costumer support from Badspot.
Also, in retail you can easily add add-ons like vehicles and weapons and such.
It's also better because you get to play with Badspot.
oh yeah and better inventory system, more paints, more weapons and vehicles aren't that buggy anymore, which brings me back to my add-ons point.
Also, it has a music brick!