I'm in agreement with Raffi's post. I learned too little to late about Network Solutions service problems, which like Raffi stated - I also had trouble with them. The bad thing is I just recently renewed one of my domains for 2 years with them, all was fine until two weeks later when someone over there messed with the DNS settings and it got all screwed up. This was after my check cleared (imagine that!). It took 3 weeks to get the problem resolved, in that 3 week time I had two contacts from Network solution - one was a very generic "we are working on your problem" email and the other was some customer service person who sounded like they barely knew what DNS stood for.
Anyway, the fact that their was a problem didn't peeve me - hey things happen, I can understand. It was the fact of the poor service in making things right that got my number.
Basically, I think the rule "you get what you pay for applies"...however in the registrar case they are popping up all over the place since the Network Solution monopoly has been lifted - this means competition.
I do recommend that before you get taken by something cheap like "$30 for 5 years" at least call them up and ask what kind of service they offer and be honest and tell them that they are a dime a dozen now and you need to know what support they offer.
PS. In all actuality you should never have to deal with your registrar unless you change/delete domains or move hosts. After all, they are really only providing DNS resolution. Finally, if you need the website too - most hosts will handle all the registrar stuff for you if you buy a hosting plan from them. This is a good deal - one point of contact , your host.