Hi There,
Currently finishing off the MSc Comp Sci Conversion at a university in the South West of England and I have to say it's been a fabulous experience in the main.
You'll probably not need to worry too much about hardcore maths for most conversion courses; however, there's always the opportunity to put your maths to use in most of the programming you'll be doing, as well as with your project / dissertation.
The admission process was nice and smooth in my experience - applied end of December, heard back second week of January with my offer.
Touch wood, and provided I don't mess things up, I'll be sticking on to do PhD after this! (And the Department have a strong track record of conversion students successfully completing)
I would say go for it :)