I had a few probems early on at RF, but nothing major recently. The worst problems I've had is their general $7.99 specials over-riding my $7.25 bulk pricing. They have fixed it promptly when it's happened though. For a while, I was getting some sales of their domain marketplace, but they have burried it since they put a new look to the site and those sale have mostly disappeared. I have a $6.95 enom account, but by the time you deduct the 3% for paying by paypal or credit card you are really paying $7.19 which is almost the same as RF. The $.06 difference it worth it to me for the domain marketplace and the simple RF domain push to an email address to a new buyer.
I recommend no one use solely one registar. I have 300 or more domains at at least 3 registrars and up to 30 at another 3 or 4. In doing so, you can take advantage of special pricing on transfers, registrations, and renewals from each. When you get up to a couple hundred or more domains, they will almost all give you special pricing. Also, if one ever gives you trouble, the fear of losing a number of domains to another can give you some leverage.