Ubuntu and XUbuntu use the same package set. Even the package versions will be the same. The main difference is that the XUbuntu has a more lightweight desktop. BTW you don't have to switch to XUbuntu. You could just install a lightweight desktop in Ubuntu if you're experiencing performance issues.
https://help.ubuntu.com/community/LXDE
I don't think there're are many bugs. If slow it's probably a misconfiguration or a driver issue.