I owned a gear shift for 15 years and never thought twice about having to use the clutch so frequently. I would grade my driveway, plow snow and haul logs, so it really was not an issue at all. Then the time came for me to get a larger tractor last year and since all the dealer had was HST, I figured I'd test drive one since they are so popular. I spent an hour on their lot and didn't really have a chance to put it to work. But I was anxious for a new ride so I bought it and had it delivered a day later.
The big day came and I was planning to spend the weekend spreading about 15 yards of loam. Inside of the first hour, I knew I had made a mistake. I would approach the pile and the machine would bog down and then finally get the balls to lift a load. It almost felt like a 1-2 second delay from what I knew. No where near as responsive as my gear was. Needless to say, I was disappointed and called the dealer and he asked me to stop by so he could "teach" me how to drive an HST, because they are clearly different than gear. Even after spending an hour learning that you do not press down on the pedal when approaching a pile, it just did not feel right to me.
Since they did not have a gear version on the lot, I drove to another dealer and hopped on a shuttle shift version of my tractor and knew in 10 seconds flat that was what I wanted. It fit like a glove. So I returned my HST with 3 hours on it and waited another 3 weeks for a shuttle version to come from the factory. Best decision I ever made.
I'll agree with earlier posts that HST is more popular because the majority of suburban tractor owners (who make up a lot of the tractors sold) are clueless how to use a clutch. There is no doubt that HST's have their place for certain types of work, as do shuttle/gear. It is a personal preference and I cannot think of a single occasion where my shuttle did not do everything I have asked it to do, even delicate task that require me to move only an inch.
While you may not spend much time using the clutch with an HST, you make up for it reaching for the cruise control.