I have a Husqvarna YTH20S42LS with a 15 hp Kawasaki engine. The engine is great; strong enough to what it is asked to do and very quiet. I change the oil every year and have had zero problems. It is a typical hydrostatic mower where the hydro pump is belt driven. One thing I do not like is that I am constantly adjusting the ground speed. It goes noticeably slower up any size grade and then quickly much faster when going down grades. I think some of this can be attributed to the horswepower of the engine. Although I have checked it out thoroughly I feel like some of the speed change may be from the belt drive assembly. I have an older New Holland hydro with a 12 hp Kohler and direct drive to the hydro pump. There is absolutely no change in ground speed no matter what the terrain is.
The mower has about 250 hours on it and I have had a lot of trouble wit the deck, especially this year. While they are a cheap fix, it has broke at least one spindle housing every year. They are a three flange mount and the flanges are pretty weak. I have been unable to get an even cut this year. I replaced both blades, both spindle shafts, bearings, and spindle housings. I have adjusted the deck every way possible but it still has an uneven cut.
You may alerady know but a Husqvarna is the same as a Craftsman and many other brands produced by YTH. There a suttle differences but they are mostly cosmetic. I would look very closely at the deck; gauge thichness and spindle size, going with the heavier built one. A fabricated deck is always stronger than a stamped deck. Are the spindles large and can you grease them? I agree that a B&S engine would be my last choice but I would also put a Kawasaki engine right up there with a Kolher plus they are much quieter. We have a 13 year John Deere with a Kawasaki and it still runs like new. I hope this helps.