Having played around with the OfficeLive Premium Beta (UK) for a few days, my first impressions are very favourable.

It certainly seems to tick all the SaaS 'must have' boxes identified in various posts on this site and seems very compelling from a micro/small business perspective.

I am pleasantly surprised at the level of sophistication and flexibility provided, particularly in the ability to create new simple 'business apps' and share and collect data from them across employee, customer and public site views. More than you'd possibly expect for what is likely to be around £20/month.

It certainly provides another significant leap in validating the SaaS model but also raises the bar for many ISVs and service providers.