I was using 1and1 till couple of weeks back, but now moved to a VPS ( cost 10 times more then 1and1 shared ) solution as it is eaiser to move to dadicated server very eaisly later. The problem with shared account is that as your site grows , it becomes painful to manage. If you think your site is going to get huge traffic or may need bigger database then you need to look for other options as well as eairly as possible.
For my site, dir.mobi , the traffic is exploding and I am making some money using admob , so decided to go with VPS route. It could be very difficult if one fine day you suddenly maxout on the resources and have to shut-down your site becuse of the resources. Also our NP member movingconcierge really scared me with his experience ( other many members) with 1and1.
Vcool
PS: It took me more then a week for my site to completly work on another host. The script that works on shared host may or may not work without any changes to the code and/or server paramenters on another host. It would take a while to completly understand and debug the problems.It is a painful process and just wanted to share my experinece.