You should go test drive a tractor similar in size to that machine that's hydrostatic so you can have something to compare it to. That does seem to be a nice price, but hydro sure is a nice feature.
I can't find info on that particular transmission other than that it has 9 forward and 3 reverse gears. It's possible some of the gears are synchronized, which would eliminate the need to stop for each shift, but I don't know. Also, since there's only three gears for reverse, it seems unlikely that it's a shuttle-type transmission which allows you to very easily switch between forward and reverse, which is something you'll do pretty often. Like I said, though,I can't find any details easily, so I could be wrong. It's possible that you can shuttle between one of the forward and reverse gears in each range, even though you don't have an equivalent reverse gear for each forward gear like in most shuttle transmissions.
Personally, I love my HST tractors. It's been said on here before that unless you know you want a geared tractor, that a hydrostatic model is probably a better choice.