you'd be amazed what we could find out by ourselves. ;)
For one: experience takes a LOOOONG time to grow in BB. You don't see it happening by arrows (as with other skills) so you need to keep track in order to be able to notice if they popped or not.
Players do pop, however mine still didn't, but I heard from others they had pops, which proves the fact that it is going very slowly.
The game effect should be prety easely to find out, since you just need to compare similar playes with diffrent experience. I'm sure if the comunity starts up this stuy we will get a prety clear view on it in about 1 season's time. And that is, in a game like BB very fast I think...
They are not your friends; they dispise you. I am the only one you can count on. Trust me.