I'd try out Path of Exile as well if I didn't have to pay to play the beta. It seems that nowadays developers have deviated away from the meaning of a beta. Why on earth should I have to pay to be able to test your game? It should be the other way round if anything!
This of course is going on the basis I won't receive a beta key, which I am 99% positive on.
The open beta will be free from June. If you pay for early access, you are simply pre purchasing cash store points with a beta key and other goodies for higher pack.
Is $10 really too much compared to preordering this game for £15?