I've seen differences of between $700 and $1000 depending on the dealer and location. Welcome to TBN by the way.
If you've ever used gear and had to push that clutch all day long, you'll love the HST. Of course, if the leg on the HST side has any problems, it can be about the same as the clutch!
I bought the HST, but I could settle for the shuttle shift just as easily. If I'm doing a lot of forward/backward motion and turning, the HST makes it much quicker for me.
Over the life of the tractor, the extra dollars don't amount to much.
John