Your previous ATI card is much better. Integrated graphics tend to suck, but at least with integrated graphics you have a backup if your main graphics card fails.
The 3100 also has trouble with custom resolutions but can output standard HD resolutions.
It's fine if you are just web browsing or playing light games such as The Sims but if you want to do any serious work like video editing or play serious games (Bioshock, Crysis etc) then just make sure your new Desktop has a PCI-E slot so you can upgrade in the future if needs be