I would disagree about the two mentioned above ... I had really bad experiance with them ... I regged three domains ... payed through my credit card ... got confirmation emails that I have got the domains regged on my name ...
... and the few hours later my registration was canceled . ... customer service sucks ... did not tell me what was the problem just one sentence description "YOUR REGISTRATION WAS CANCELED"
I think if you send somebody confirmation email about registration it should mean that you actually regged the domains and not just be a spam
... well that just my opinion maybe other people had wonderful experiance with both ... but not me