I have 35 acres here that is a lot like you described your place and 3 acres down in Florida. I maintain both with my tractor. I also cut my grandmother's pasture a few times a year to keep the weeds down (12 acres). A 5ft brushhog does the job exceptionally. My tractor is an L3130.
Both that you mentioned are great tractors. I know that doesn't help much, but just a thought. As for HST over gear...man, I've driven both geared and HST. HST is the best thing since sliced bread. You won't regret getting HST...that's for sure.
As for PTO power loss caused by HST leeching, it's negligible on the two models you mentioned. You won't even notice it, especially on a 6ft bushhog, with that many existing tractor hp.
As for a smaller tractor with that kind of mowing acreage, you'll be spending a little more time in the seat, that's all. Smaller tractors can perform 95% of the jobs a slightly larger one can, but it just takes a little longer...depends on how much time you have!
Oh...not sure if the warranties are the same, but no matter, Kubota's don't need no stinkin' warranty
...just kidding all you JD owners.
One last thing. I wouldn't pay 2k for a landpride 6ft bushhog! That's high for this part of the country...really high! I just bought a 5 ft. Rhino with slip clutch for $1236.00 out the door from my local JD dealer. I looked at Landprides at Kubota and it was cheaper for the same size, but I liked the sloping atop the Rhino's better. Doesn't hold as much dirt/debris and water, so it won't rust out as quickly. Don't fall for that bs. I feel you can do better. Someone is trying to pad his bonus check.
Podunk