I have two pro's, two MP ltd editions, and an S. The pro's are really solid but you have to be strong - they are heavy. I use my pro's in the summer outside on the clay when it is warm.
I use the MPs, which seems to swing lighter and easier, indoors in the winter when it is cold.
Both are solid, but the pro seems to have more plow through. The MP is better on serves though because i can generate more head speed with it.
I string the MP with TF X-1 Biphase mains and TF Red Code crosses. Both 18.