I have been a v1 Parallels user. I used v2 (and all the problems that came with it). I also tried VMware Fusion 1 (didn’t like it much, it was slower and I already had Parallels). Then VMware 2.x was out and Parallels 3 (and a mess with licenses appeared). I grew tired of Parallels and switched to VMware. It felt slower but was stable and people liked it.
I Ignored Parallels 4 (mainly because I was a happy VMware user and didn’t have time to switch back).
Now we have VMware 3.0 and Parallels 5. VMware 3.0 is nice, has nice features but also a boat of bugs and it doesn’t deliver what I expected. Unity is still slow as hell. I brought the upgrade from 2 to 3 mainly because I didn’t know Parallels had a 5.0 ready.
So I downloaded Parallels 5.0 to see if it was “as slow as Fusion”. I got shocked. It’s way faster. It has bugs. I’ve found a lot of small things. It’s a “.0” release. There are things that could be polished. But I’m seriously considering switching back to Parallels.
And I’m using converted VMs from VMware. When I get my W7 copy I’ll simply install the VM with Win7 + VS2008 + all the stuff I need to work. Given the mixed reviews I’ve seen, Parallels seems to be faster than VMware.
Now, Parallels 4 vs 5 seems to show (According to the forums) also an increase in performance.
There’s marketing. I mean, the engine is faster, surely, but there are also more controls for dynamic allocation of resources and idle when the machine is not doing anything, etc.
I personally can say that GDI+ (I work with .NET/C#/Winforms) and compilation of my project (about 22 big C# projects) is noticeable faster under Parallels. I run my SQL 2008 on a WinXP VM and running both VMs with parallels makes the APP react way faster. This is a perception as I didn’t conduct “tests” but I immediately saw the performance increase when I opened my VStudio inside Parallels, did a svn update and rebuilt.
Some people in twitter are reporting the same and some the opposite. I guess that you might want to check #parallels on twitter to see more “real time” info about either. It’s a mixed bag.
Coherence is > Unity in terms of how the windows move and feel. Also VMware 3 + Unity + Exposé = FAIL. The windows don’t show the content… in Parallels that works.
All in all, I’m happy with the Parallels trial (still a few days to go) and might go back to it.
I don’t know much about “gaming” in the VM as that’s now that I use it for. But Vista with AERO, feels snappier under Parallels.
Hope this helps.