Macbook Air: Parallels or VMFusion

I've just ordered myself an 11", 1.6Ghz, 128Gb Flash, 4Gb RAM MBA.

I need to run Windows 7 on it for a couple of Windows only programs.

I have unused licences for both Parallels and VMFusion which I run on my iMac.

I find it hard to notice much of a difference in performance between the two and they both have their pros and cons with regard to UI.

Would there be any benefit in one over the other when run on a MBA with the above spec? Battery life? Processor drain? Flash storage usage?

I'm only planning to run some number crunching software under Win 7, nothing too graphics intensive.

All advice appreciated.

I've recently installed Window 7 via Parallel. It's fantastic. Parallel gives you full screen, widows, or coherence, where you are mainly in OSX but still have access to all Windows programs, documents and startup menu. Don't know much about Fusion, I'm sure it's good too. My MBP 13 run Parallel and Windows 7 comfortably. The MBA even though with less specs should be OK too. I've set mine to 1GB of ram allocation for Windows for a while and it seems to be OK too, though I didn't do anything strenuous.

moved.

I recommend Fusion.

VirtualBox from Sun also runs these fine (I use it to run Ubuntu on my MBA 11 with only 2 GB of RAM). I have also used it to run Win7 on an older Macbook C2D (from 2007) with only 2GB of RAM and it runs fine there too. VirtualBox is free, which is an added advantage. Both Fusion and Parallels will work fine and have more features, but also cost $$.

Cheers