I had phoenix 4 (s, I think) on a windows 7 machine and got the "upgrade to 5.0" a number of months back. I've been around long enough to not jump until the beta testers get done with such upgrades. I just downloaded 5.0 and it seems to work fine. The download was painless but lengthy as there were a lot of files and tutorials. I haven't gone through everything in detail but I do think it is an improvement over the most mature version of 4. I have not messed with model builder yet. I can say that the servers were updating this afternoon. I even downloaded some more models.