I've used them. The reliability is terrible; at one point the entire system went down for several days. I've also had numerous other problems affecting my account there. The support staff are really nice, and pretty responsive, but that doesn't make up for their systems being broken.
For my needs (occasional access to a windows machine, cheaply) all this wasn't a big problem. Maybe if what you need is just a uk-based account for occasional testing, it'll be OK for you as well. But I wouldn't use them anywhere I needed even a little reliability.
I believe it was myself who posted on the other list. FlexiScale certainly has had it's issues this year, there is no doubt about that, however we are all extremely confident about the new release that will be coming out in Q1 of 2009, and would really like to get people to try it.
We will also be issuing a full detailed decscription at that point of the internal issues we faced, to explain how we've overcome them.
Anyone who wants to try it at that point is more than welcome to a no-catches free trial, so we can prove we are delivering on our promises.
For my needs (occasional access to a windows machine, cheaply) all this wasn't a big problem. Maybe if what you need is just a uk-based account for occasional testing, it'll be OK for you as well. But I wouldn't use them anywhere I needed even a little reliability.