I agree with David, I'm just finishing my IR at Stapleford now - should be doing my 170A at the end of this week or beginning of next.
I've done my PPL right through to IR with SFC, and I've also done a fair bit of different types of flying at other places in the UK. PPL-wise I think it can depend on who your instructor is at Stapleford but generally they're pretty good - personally I had an excellent PPL instructor who prepared me well for the CPL.
It's a similar story further up the ladder; my CPL/ME and IR instructors have all been absolutely first class - I really cannot fault them at all. The only minor problem I can think of is a lack of standardisation between the instructors at Stapleford. Even so, they seem aware of this so, where you have to fly with other instructors occasionally, they usually arrange for someone with a similar teaching style to take you on for that slot.
I agree that, for the money you pay, the aircraft are generally a bit old and tired - particularly at PPL level. I worked for a different flying school during my ATPL studies (we only taught up to PPL) and the aircraft were in great condition, but the instructing was, with a couple of possible exceptions, nowhere near the mark of SFC - and I know what I'd rather pay for!
I have no hesitation in recommending Stapleford as a great place to train for anything from PPL through to CPL/IR.