Advice on Mobile Broadband Provider

Can anyone advise as the best mobile broadband network? I'm currently using O2 but speeds and reliability have gone down and they've also off-loaded theCloud WiFi which was a useful plus for me. Not a particularly heavy user but speed, reliability and coverage are important.

Since my contract with O2 is coming to an end I was thinking of either 3 or Orange, but I thought I'd ask here to see if I should avoid any of them like the plague...

I'm mostly in the Stoke, Nottingham, Birmingham triangle. Also I use Mac OSX so any software needs to run on that.

Edited by Tacitus (Wed 29-Feb-12 12:00:13)

From what I've heard (from friends), steer clear of Orange. With 3, however, I've always had great data service - just pray you never have to call customer services!!