Just joined as well! 235 TH! Have been waiting a while to join this pool until you got another committed big player. Looks like sidewinder here to stay, so I am too. Hope others follow suit and we keep getting more to join the pool. 
Welcome aboard - can see you there in the list 
Yep the 10BTC is there to get more like sidewinder on board to help reduce the variance for everyone.
Everyone else still gets the best pool fees of any pool worth mining on - but it seems that's not enough to bring over large miners like that, so I need a carrot also to get some more