i honestly cannot tell you
i have used both for quite a long time
RPS always seemed to big good, sometimes a little large or slightly inconsistent, but on the whole, an excellent paint which has good breaking skills or whatever.
of course it does depends what RPs paint you are talking about, euroflite which is or should be training paint, is hard and doesnt break to much, hell one tourny we used some, and the team complained to us saying they were being hurt cos they were hit 10 times with bouncers!!! Marballizer/slam ball/el tigre/all star made by RPS are all the same paint, just different shell designs/colours.
Dracula site paint i found to be ok, good breaking on things etc, the tourny paint is consistent, and has a seriously thick fill, im talking worse than syrup! also, if you drop it from 4 feet, it breaks on the ground
, so its good for guns soft on paint, like cockers, but not good on guns that are hard on paint
also, beware, if you have a bad experience with a paint, doesn assume automatically its crap, sometimes they just have bad batches, tell whoever you bought it off and they should replace it, ive had batches of paint to be bad one time, then excellent the other!
edit: as said below, the paint sizes are different,
the marballizer i used gos as follows, the pink i used a .693/.695 freak insert, for green marb i used .689
for dracula, i was using .689 i believe