Played with them for 3 odd years now. ALWAYS received payouts to date. No jackpots (yet! ) but no question of payment to my account. The support people are also friendly (one niggle would be that they actually call you too often, and sometimes when you're at work on support issues). Otherwise they're fair dinkum.
I saw a negative comment regarding them not disclosing info on previous players winnings which I thought was a bit lame. In my opinion and unless you're an utter plonker, you should never publicize your wins. I'm pretty sure they'd love people shouting about winning on their website but have to respect players wishes if they want to keep those players??
Imagine walking into a casino and stating that you're not going to play unless the house tells you who's won how much and where they are from! They'd tell you to ***** off! Haha
My brother's friend actually worked in their accounts dept in the UK and also said that they are kosher.