Hydrostatic, HST or HSD are all pretty much the same thing from what I can tell. Basically think in terms of an automatic transmission on a car, only maybe a bit easier. Push one pedal and the tractor goes forward, push another and the tractor goes in reverse. The farther you push the faster the speed. Heck even the lovely Mrs_Bob can do that /forums/images/graemlins/grin.gif
Gear transmissions can loosly be lumped into the following group: Syncro versus mechanical versus sychro shuttles or shuttle syncs are all versions of an old manual transmission. Synchro shuttle being the most advanced and easiest of them to use and probably the most productive of the bunch.
Not that I want to start a "gear" versus "hydro" but for real farm chores like plowing, gear is simply better. For tasks like FEL work, then hydro is better. Those are my opinions, but they can be reasonably backed up by industry where productivity is measured in dollars and time, nearly every type of lift truck or loader today is hydro transmission. Gear will do pretty much anything a hydro will do, and visa versa, but you have to get used to either one and you will get good at either one. Hydro is typically easier for most folks who use a tractor around the home, typically the "estate" tractor users and many of the smaller tractors now only come in hydro versions (sub CUTs). Hydro costs more up front, has a higher resale value down the road.
On the Kubuta website the 3130 is an
L3130, might be listed as a Grand L series. It is, in my mind, the king of the 30hp tractors, with specs and refinements that simply outclass everything in the market, and typcially at a good price. Not saying it is the best choice for everyone, as it is a large tractor for some serious work with a FEL, backhoe or blades.
I think the 30 hp class of machines probably causes lots of confusion among buyers (or maybe it is just me /forums/images/graemlins/blush.gif) because there are so many to choose from, and each seems to be very unique. There are value machines with only the basics, there are small light machines with lots of deluxe features that are great for use around the house, there are big beefy units that are far more capable at work tasks and there are things that fit inbetween. Comparing the specs only on 30hp tractors doesn't allow good comparisons. Decide the tasks and then fit the tractor to the task. FOR EXAMPLE: If you need to mow the yard, you don't want a big heavy machine, you want a small nible light unit, but both will have similar PTO hp and power the same size mower deck . . . but only one is suited for the task.
As was mentioned by someone else in the thread, the dealer can make all the difference. Big or little doesn't matter, what matters to me is quality and care. Will they take care of me? Will they have the parts in stock or the experience in the service department? Will they take the time to show me why their machine on their lot is wrong and why they need to order in the right size & configuration for my tasks or will they push what they have? Will they bring it to my house and let me demo it?
When I bought my New Holland the guy didn't have one in stock, I didn't want to buy without a touchy feely experience, so he ordered exactly what I asked for, but with no obligation for me to buy. When I bought my Ventrac, the dealer brought it to me (about 200 miles one way) for me to demo it, no obligation for me to buy. I've been dealing with my Kubota/Case/Cub dealer since before I moved to my property, he and I are on a first name basis and I've gotten several pieces from him including a Kubota
B2910, a Cub garden tractor, and a couple ZTRs. There are 2 John Deere dealers within a stones throw of me, one is pretty much a jerk where I have TRIED to give them my money to buy a tractor but I couldn't get a saleman to talk to me! The other concentrates on smaller equipment and mostly deals with suburban lawn owners and landscapers, he doesn't seem to need the customers who have a few acres and need some real attention. So I absolutely second the statement that the dealer makes the deal, not the color the tractor is painted.