I can certainly say that Cloud4 provides outstanding service, and has some of the most innovative cloud services in the UK. Our solutions are based around a simple phylosophy of providing a more comprehensive service than the market leaders, for less!
Cloud4 was one of the first 5 providers in the UK approved by Mirosoft to launch hosted exchange 2010 to it's 12'000 users, which gives you an idea of the skills. Also, in over 3 years have never lost a client to another provider, which says everything you need to know about the service.
Add to that the ability to provide flexible solutions that actually meet clients requirements, where many providers require thier "clients" to be the flexible ones. And I think Cloud4 is pretty good.
But, I guess my opinion doesn't count here as I am the MD.
I would be very interested in, and welcome the comments of any business that has dealt with us.