I don't even think this is really even targeting companies who are thinking about virtualisaton. I'd guess the early adopters will be the companies already using desktop virtualisation of some sort or another who already find it a management nightmare.

This sounds expensive compared to a stand-alone PC, but in terms of all the licensing and hardware required for in-house virtual desktops, it's reasonable.

The big difference is Amazon is now taking the 'risk' for sizing the infrastructure for virtual desktops. No need to estimate capacity for servers or licensing. Ten users next year, a thousand? You know it's going to cost you $x/user/month and no more sweating about server capacity, license compliance or negotiation.

Amazon 'Direct Connect' would also probably be a necessity for a good user experience, again limiting this to the pockets of people who'd already worked out thin clients were 'worth the trouble'.

Given the monthly cost of these is lower than the equivalent 'On-Demand' instance cost, it wouldn't surprise me if they had some sort of over-subscription 'special sauce' in the mix as well. Everybody doesn't flog their desktop 24/7...