Let me begin by saying that I have been, and probably will continue to be a firm fan of VMWare Fusion for Mac.

I’ve used it every day for the last 4 years right from version 2.0.1, for developing on the Microsoft platform, and most especially with SharePoint. It has been rock solid, reliable and dependable without question, and with each passing upgrade things only got better – slicker UIs, new and improved features, faster performance etc etc.

I my opinion the culmination of this was arrived at with version 3.1.3, quite literally “Best version ever”!

And then things went wrong….

Version 4, which I eagerly upgraded to, promised much;

• Completely revamped UI
• Faster snapshots
• Improved snapshot management
• Faster suspend and restore
• Pause running Virtual Machines
• Improved performance of Windows guests

Initially things were fine, I noticed some improvement in Windows guest performance, although restoring and suspending guest VM’s didn’t seem improved.

The snapshot management interface is simply beautiful.

Though after a while the problems started;

• Running up a guest VM using it for a bit and suspending was fine
• Banging away at the VM all day with SharePoint development (VS2010, SP2010, SQL Server et al) would, 9 times out of 10, completely hose the VM’s suspend feature, such that after choosing to suspend the VM it would close down pretty snappy, then trying to shutdown the Mac would fail and simply wait with the spinny beachball for hours, actual hours before eventually the Mac would close down.
• I began to notice strange and subtle virtual hard drive corruption taking place, SQL Server database suddenly becoming corrupted and requiring a DBCC, or worse requiring complete reconstruction
• Unexplained and unexpected BSOD’s
• Increasingly sluggish performance as the day worse on

I began to suspect (with the help of Activity Monitor) that VMWare Fusion, in its attempt to appear quicker, was doing quite a lot of stuff in the background, such as flushing a virtual machine saved state and snapshot deltas out to physical storage – and quite slowly at that.

I got to a point were I could not use it as a development platform for my day to day work – I need consistency, reliability and most importantly dependability, and so I reluctantly looked at the alternatives, which brought me to Parallels Desktop 7 for Mac.

Reading over the technical literature, and scouring the net for reviews revealed pretty much feature parity with VMWare, fine, claims of huge performance figures running Windows virtual machines, dismissed as marketing hype. I downloaded it with a free 14 day trial and have been using it for the last week, day to day as my main SharePoint development platform.

Ok, so here is my summary;

My host machine is an 8GB Macbook Pro 2.53 GHz Intel Core i5 with a Crucial 256GB SATA III SSD

My virtual machine guests reside on an external USB 2.0 hard drive

I typically run Mail, Chrome, Skype, Twitter, Evernote and iPlayer on the Mac alongside my virtualisation host

The VM’s I use are allocated 4GB of RAM and 2 CPUs

• The performance hype wasn’t hype, I don’t know how they do it, but running a Windows guest VM loaded with my SP2010 development stack is freakin’ fast, not just fast it’s so close to a bare metal setup you wouldn’t know the difference.
• Parallels has an adaptive Hypervisor which you can configure to switch resources to and from the VM depending on whether your VM or a host app is active.
• Suspend and restore isn’t particularly fast, perfectly acceptable and seems consistent.
• Taking and restoring snapshots again, isn’t particularly fast but perfectly acceptable and seems consistent.
• Pausing a running VM is a provided feature.
• After suspending a VM, the Memory monitor on the Mac informs me that all memory has been returned back to the Mac.
• Shutting the Mac down immediately after a VM suspend works as expected.
• Parallels has a nice feature whereby, having created a VM, once you get it to a nice point, you can create a VM Template out of it, after which you can use that template to create new VMs out of.

Now for some balance;

• The user interface is not as slick as the Fusion UI, it’s much simpler (in fact it’s more like the Fusion v3 UI) – this I like, simpler is better in my opinion, if you love the slick UI of Fusion, this may be an issue for you.
• The keyboard handling in Parallels does not match the sheer seamless keyboard handling found in Fusion – you’ll probably spend more time in Parallels setting up keyboard shortcut mapping than you would in Fusion.
• There are more UI modes in Parallels than in Fusion, and this can be confusing.
• It’s harder (configuration wise) to ensure that your Mac environment is completely separated from your VM guest environment – what I mean is, there are more integration options available (which I want to turn off) in Parallels than in Fusion.
• Parallels windows don’t seem to honor my Mac OS X Lion virtual desktop preferences, no matter how many times I select “Open in this Desktop”.
• It’s more expensive than Fusion (£69 vs £49), although both vendors have offers going on right now.

Of the negative points, the only one which is an issue for me is the keyboard handling – this I find annoying but it’s something I can live with and manage (I find myself creating explicit keyboard shortcut mappings as I go).

As my trial period comes to and end, I’ll be buying a licence for Parallels, even though I recently bought a new licence for VMWare Fusion 4, for me the two key features which are the compelling selling points are;

• The dependability – I’ve deliberately been stressing the VM environment and the Mac on which it runs to see how it copes and so far I’ve not been given any cause for concern, as the Apple mantra goes “It just works”.
• The performance – trying not to wax lyrical about it, but it really is eye-opening

I think VMWare have dropped the ball with Fusion 4.x so far, trawling the net turns up a significant number of other people experiencing similar problems with many returning to v3.1.3.