We purchased new 90xp which is the better of the model (wider chute, 85hp, heavier frame, larger wheels, etc.) Was a very good machine. No problems............however, 3 years later traded for 250xp...totally different machine. Should have purchased it in the first place.
If all he is going to chip is smaller limbs( 9"), the 90 should be fine though.
With regards to removals and larger limbs.. go larger. Remember, size matters.
90xp probably would have been a little better if it was a diesel.
We all know the diesel is best way to go.