The best thing I like about Parallels is that

it EXTENDS Mac's trackpad swipe to windows applications. Now I can swipe in word, excel, powerpoint, you name it and have not found a single application that you can not swipe. I have 6GB RAM on my Macbook pro, and assigned 2GB to Windows 7x32. Very very smooth. Under Parallels I have XP and Ubunto 10.10 too, although have not used them. Just in case. :)). Another cool feature is that when you plug in a USB drive, parallels will ask you which OS it is for. Very nice. Highly recommend.