Wow. Not sure my opinion could be more different. Sure, it's just my opinion, but I do try to avoid blanket statements like "However the best value is as previously stated." While I may try to give my reasons for what I purchased to someone who asks, I fully accept that while what I purchased may have been the best value for me, it is not possible to lay down a definitive statement saying that "this is the best value".
Not sure where you got your information that "Deere speeds up the engine RPM and calls it a different tractor", but the specs for the two engines are different AND all horsepower ratings are given at the same engine speed of 2600 RPM. The 4310 has a 92 cubic inch engine and the 4410 has a 101 cubic inch engine, thus the HP difference, not from increasing the RPMs.
As for HST vs 12/12, my opinion is exactly the opposite. I feel that long, uninterrupted movements such as mowing lends itself much better to the 12/12. I also think that 12/12 may be a better choice for serious ground engagement, such as plowing several acres. However, the HST stands above the 12/12 where repeated back and forth movement is required, such as loader work. This was going to comprise a lot of my use for a CUT so I never looked at anything other than HST. Try creeping up to the side of a brand new pickup to drop a load of gravel in the bed with a 12/12, especially if you're going slightly down hill. Sure you can do it by with one foot on the clutch and one on the brake, but I feel a lot more comfortable creeping up with my HST that stops when I lift my foot. I also feel more secure working around structures knowing that if the pile of horse manure I just stepped in causes my foot to slip off the pedal, the tractor will stop instead of plowing through the side of the barn.
As for "But the 12/12 has a distinct advantage in several areas including power, longevity, maintenance, noice, and pirce", I'll give my opinion on each.
Power: You're right. The HST does cost 2-3 PTO hp. But, it is enough power for all the pto powered implements I use plus the HST will still spin the tires before the power bleeds off when pulling, pushing, etc.
Maintenance: Again, I'll give you this one. The HST does require that you change the fluid and filter at 50 hours and then every 200 hours after that. However, this may be less trouble than replacing a clutch and pressure plate.
Noise: The only time I've noticed noise is when you let up on the pedal and the tranny is winding down. In use, I don't notice any noise louder than the diesel motor noise.
Price: Yup, the HST costs more initially, but so did the automatic trans in my pickup when I purchased it. If you want it, you pay for it.
Longevity: Saved this one for last. Maybe some actual tractor mechanics or dealers can chime in here with MTBF for each tranny, but my experience does not lead me to the same conclusion. For 5 years in the early 70s, I worked for a city water dept. I observed the use and maintenance of our two backhoes for the first two years and was an operator for the last 3. They were both IH hoes. One with a gear shuttle and the other HST. The HST was on the "big" tractor with the extend-a-hoe so it saw the most use. In the 5 years I was there, we NEVER had any trouble with the HST on that tractor. And these were machines that saw hours of use at least 5 days a week. Granted, we never had any trouble with the gear/shuttle tranny either, but I would guess that these tractors saw more use in one year than the average CUT would in 20.
Again, everything above is just my opinion based on my needs, uses and experience (with more than just CUTS).
Hoss
