I’ve been on Parallels for years and mostly w/out issue. I use mostly for XP Pro and office apps and have yet to find any huge issues. Each rendition of Parallels seems to make huge strides in performance.

Recently (March – May 09), the one issue that I did have was that Parallels lacked the ability to run server editions w/o the need to buy new software.

So I was turned on to Virtual Box which not only is free, but also supports servers. I thought this was too good to be true, and I guess in some ways it was, others it performed just awesome!

1) Virtual Box installations: Ubunto, MS Server 2008, MS Server 03) All had versions installed that were ADS, IIS,
2) VBox allowed for “intra-networking”, something I haven’t seen under the other virtual machines.
This allowed for me to setup (IE give a name to network connection) with VBox managed as a virtual network. Not external connections, but allowed me to do all the Server testing I wanted in a safe non-internet zone and it was a beautiful thing!
3) Important! RAM Mgmt: This is NOT dynamic, so you MUST manage your RAM allocation according to how you plan to use your VBox machines.
I had 2gb RAM and at 1st I was allocation 1/2 to OS X, 1/2 to VBox, but once you added another VBox machine, you were out of RAM which will cause a machine to NOT be able to start until you make the needed adjustments. So with 2GB ram and 7 VBox Machines installed, knowing that I would be trying to test as many as possibly, each machine was alloted 256-350mb which actually was more than enough for small testing.

Here are a few dislikes, followed by one very impressive plus!

Few Dislikes:
What I didn’t like about VBox was that despite installing “tools” like in Parallels, it’s attempt at sharing assigned resources (IE: h.drives, CD/DVD, USB, etc) would not not be allowed if another VBox was running and using them. While once the OS was installed I didn’t need such devices, This was annoying since you had to constantly mount and unmount each device.

Window/screen size, I was NEVER able to find out how to increase the actual screen size in VBox. After installing tools I was able to increase the window size, but the screen itself still remain 800×640 which was a little annoying.
There was a plugin for Ubuntu, but that required a manual install that I never seemed to get to work.

The part that not only I, but my Prof. was impressed with is that I was able to run (at times) to run up to 5 VBox Machines with OS X. Yes, 6 OS’s running at one time and with uptimes as long as 5 days without so much as a blip (barring any small issues mentioned above).

My mbp DID suck down some battery juice, but rarely ran fans at fullbore.
In the end I was able to accomplish all my installs, and in total 7 projects that spanned from Directory Services, to ADS, to IIS Web services.

So VBox came through where Parallels and I believe VMW may not, but it’s still a tad clunky. But Hey, It’s FREE & got me the A!!

I would rather use Parallels Desktop for the simple fact that it is kinder on my cpu and the overall performs of my mbpro is much better especially when IE7 is running all sort of messy active control x based code for over 8 hours at a time.

I have since moved on to VirtualBox (v1.6.2) and absolutely love it! I get much better performance and overall system response on VirtualBox than I ever received in Parallels.

I am deleting Parallels from my Applications folder and I’m not looking back.