Yes I was invited to the Beta....
Parallels 4 seems to be MUCH more User Friendly, and easier to use...
HOWEVER..... I have 2 OS's I use on Paralells: Windows XP, and Windows Vista..... When I loaded Vista a million pop-ups came up at me saying my Ethernet Card, and my Floppy drive, as well as the CD Drives hardware could not be found.... And then after I got that resolved and I had been playing around with the Virtual Machine, it crashed and said Windows/Paralells encountered a Fatal Error (not BSOD) I am sure they will resolve that issue....
XP Seemed a LOT faster, and I didn't have as many problems with it as Vista... the only interesting thing is: When I turned it on for the first time Windows gave me a pop-up saying that because the computer has gone under a massive amount of Changes it needs to be re-activated...
Overall it's a step in the right direction for Paralells, but there is work that needs to be done to improve some of the features.