My missus has done a couple at Dales mtb in Reeth – she has got so much from them and she has really shifted up in riding skills. I did one with her a few weeks ago (Steep & Rocky) and realised I was descending completely wrongly – I also feel transformed.
As above, depends what you're after and whether you "click" with the instructor, I suppose – we both really got on well with Nicola at Dales.