Paul Dwerryhouse at Nepotisima has reviewed Dapper Drake and is looking at the pro and con's of it – and he ends up liking it too.
Read the review here
So, when and why would you choose to use Ubuntu? I would have no hesitation in rolling it out in an office environment, where the primary applications required are a mail reader, office suite and web browser, and where multimedia applications are fairly low in priority. And while I may not use it myself, the prospect of paid support from Canonical is likely to be a good way to swing management types on board, also.