ryeokum-
First of all, welcome to TBN! I am still a fairly new member, but I can assure you that you will find many expert tractor owner and operators in this net.
I recently purchased a Grand
L3430 (last July). One of the big questions I had while shopping for an appropriate tractor was whether or not to get the HST. My only other tractor ownership experience was with an older, small Massey Ferguson HST. When I posed the question, most people would ask me what the terrain of my property was. Many told me that up to 20% of the tractor's power could be used to move the tractor, especially up hills, thus reducing the available HP to do other work.
Since I have 40 acres of trees, many of which seem to fall down on their own, and much of my property is steep, I opted for a fully sychronized gear transmission. The 3430 has about 35 gross HP. I was a little concerned about having to shift in the hills, but it is not a problem.
I had rented a J Deere 4320 HST before I purchased my Kubota, and it did OK, but I think was because it had a turbo engine.
Bottom line: If your property is mostly flat and you want the HST, get it. Most people that have them love them. If your property consists of steep hills, consider the gear drive. When you go up or down a hill, for safety's sake, you find a gear and stick with it until you find a flat spot to change gears.
Best of luck to you.