Mira Super Sport, as said above. Simple to use, but very clever on the inside (I know a shower designer at Mira ;-).
As Toys says, warranty is VERY good – helped enourmously if you keep the orginal receipt in a safe place….. If you're in a hard water area and use it alot, don't expect the heating element to last more than 3 or so years, but they are easy to replace.
As an aside, I hear that the piping and electrical fittings and locations are being standardised over each model 'range', so even if choose to replace it in a few years you should be able to bolt the latest model straight to the wall without redrilling the fixings or moving the pipes around.
Oh, yeah, and a mixer will be better if you have a combi. Mira Combiflow (IIRC) is good and good value.