Hello, the main difference is the current rating. I think IRFP250 should be the best choice because the current rating is higher. It is better to not operate device near their maximum rating.
The 250's have greater current capacity, but twice
the capacitance of the 240's and 244's. They will
give a better bottom end, and will sound a bit
different, for better or worse, depending on your
situation and taste. There is very little practical
difference between the 240's and 244's.
