I just installed my first set of clipless pedals on my mtb and have another set for a new mtb build and really think they will work well in these areas mostly becuse the shoes have to be very hard and this aids in power transfer.

I can pull off speeds of nearly 60 kmh in a sprint with old school toe clips and my non cleated riding shoes and this is because I am a very efficient pedaller and strong rider... I have gone better than 50 kmh on my mtb with half step pedals and when I ride with friends I am regarded as one of the best climbers in our group despite being the only guy without clipless pedals.

I went on some test rides and had no difficulty clipping in or out and perhaps this comes from still using those old fashioned clips and straps on many bikes which I am very comfortable with.

I can also see them helping when the rides get wet and keeping your feet securely attached is a plus.