I see two different debates going on here.
1 - HST vs. power reverser on otherwise like machines. Most would agree that the gear tractor is marginally better for field work / pulling heavy loads because it get's more power to the ground. For rough loader work they are about the same if the gear operator is very good. For precission loader work, snow blowing or anything that fine variation of speed without impacting PTO speed the HST is better.
2 - HST vs. power reverser of the same price. Here is where it get's more complicated. Field work / pulling heavy loads the bigger power reverser obviously wins. Rough loader work the bigger power reverser wins (like moving piles of anything). For snow blowing, I'd say the bigger power reverser wins. Sure, the HST operator can slow down for the drift, but the power reverser operator either wont have to slow down or if he does it's because he was going faster than the HST operator to start with or using a wider snowblower. For precision loader work the power reverser operator will probably go slower than the HST operator since speed cannot be varied as much. On the other hand, he may use a larger heavier implement / bucket and get more done with each pass. In situations where the task is well below the capabilities of the tactor, HST wins hands down - But otherwise I don't know.
I have not looked closely at the market to see what you can get in a power reverser for the price of an HST at every price point. My budget was $20,000 and at that price point power reverser wins because I'd be down a frame size in an HST.
For the future buyer who is trying to decide between HST / power reverser or other gear tractor, it really depends on what they want to do. I push trees over, skid them, do ocasional landscaping, move a lot of snow (many driveways), maintain a gravel driveway and do hay rides in the fall. Not a single one of these taskes could be done better by going down a frame size and getting HST.
However, if you have multiple operators, want to maximize productivity for a certain weight tractor (trailering considerations) for mostly loader / landscaping work, are doing mostly work for hire and can't afford to have an employee bump something, are not experienced with gear tractor operation, are not concerned with maximizing pulling power to the ground and can afford it, than the HST makes all the sense in the world.
If someone is looking to purchase, they need to figure out what they need their tractor to do, how much they can spend, and at that price point what size tractor / tranny combination makes sense. It is not as simple as HST is better or power reverser is better. In some cases, a gear tractor with no reverser may be best because you can get a beast for the same price as a fancier tractor.