Their Motherwell careers were both before my time so I only know their records down south, purely basing it on what they have done post-Fir Park.
It's quite strange to be talking like this when my only first-hand experience of Brian McClair as a Motherwell player puts him firmly in the Top 5 worst I have ever seen!
Obviously Lambert's success in a Champions League final is the pinnacle of the club game, but if we're talking post-Motherwell careers and sustained success, I can't see a case for anyone above Brian McClair.