I booked two ski lessons as a late Christmas present for my husband, one morning and one afternoon. The drawback was that we had two different instructors - one for both sessions would have made much more sense. I don't know if you could specify that.
However, both lads were young and enthusiastic, and it was useful to have such individual tuition just before we went on our annual ski holiday. Those having lessons get priority access to the button lift, although it isn't very clear and we did feel as though we were pushing in.
The changing rooms were clean and warm, staff helpful and friendly, hired equipment was easy to access and all new and shiny - although that won't last!
The lessons were expensive, but skiing is not a cheap hobby and it did help prepare us for our hols. We enjoyed it enough to be going back with our teenage boys in April.
Just as a footnote, I have generally heard that they operate a strict policy on attendance and time keeping - which can be challenging as the traffic in that area is often unpredictable. So long as you know that's their policy, anyone booking in advance needs to be mindful of it. Another option is to book when you arrive, although there is a risk that it may already be fully booked.
Generally a good place and an extra string in Manchester's bow - a more flexible booking policy might earn more friends and loyalty than the current system.