I recently registered several domain names at 1and1... First I'm really disappointed by their domain control panel which is not flexible and complete AT ALL. We cannot even manage zones correctly.
Secondly there's no place where we can register a name server, and the support staff doesn't even understand what it means. I asked godaddy's tech support for the same thing a few months ago and they responded within minutes clearly. With 1and1 it's been a week and I'm still trying to make them understand my problem. Since three days they even stopped responding to my resquests.
Last, but not least : When I first registered the domains, everything went fine... but 4 hours after having registered the domains, they we're still not registered, every other single registrar were telling me that they were still free!! Can you imagine all the problems that might happen? you can be two at the same time to register the SAME domain !
Let me be clear: I already had problem with godaddy's tech support, in particular with dedicated servers. but it was FAR ahead in quality than 1and1.
I strongly suggest you to register your domain names at godaddy's store. You'll pay a bit more, but the control panel is complete and stable, totally the opposite of 1and1. And the support is maybe not always accurate, but it is fast, and in general they are qualified.
Is the 3$ difference between godaddy (9,99$) and 1and1 (6,99$) worth the control we lose over our domains? For me, definitely not. Maybe for someone who doesn't need advanced features it will be good enough, but even then, I would recommand godaddy over 1and1 anytime.