Even if I did not a good experience with 1and1 overall, I'll try to do this evaluation as neutral as possible.
I have been with 1and1 for a couple of months, first for the domain names, and after I try the hosting solution.
The good.
-The domain names are cheap. It is easy to setup and there is mostly all options you can think of.
-The hosting have changed these past days. 9,99$ for 100GB? That looks good, but... is there someone who can confirm this? I know that they recently bouth another company, mabe this is what it is all about.
-90 days money back guarantee, but look in the ugly.
-You can use modrewrite, read the faq and their website :)
By the way, 1and1 and GoDaddy are the two biggest competitors in the domain name hosting area.
The bad.
-My favorite answer is when you send them an email you get this :"Thank you for your recent e-mail. We expect to answer your email within the next 12 to 24 hours." And trust me, they do take that much time. This company is in UK, so, sometime, when the Americas are up, they are sleeping and vice versa.
-They don't use cpanel. So if you want to take all your stats from, let's say awstats, and transfert them to them, you can't. They have their own pannel.
-They subsystem is weird. Your ftp username won't be joe@yourdomain.com, it will be 345456567@dynipstuff.net . And it is like this for everything.