Bought that exact combination (except only 1 rear remote) in April.
Your price is right in line with what I paid.
I put R1 (Ag) tires on mine, much better traction in the snow. They're also okay for mowing as long as you remember not to turn too sharp, especially in 4 wheel drive. The tires came loaded as part of the original deal, I HIGHLY recommend loaded tires.
I have no problem at all with the power. My previous tractor was a John Deere 750 which was rated at 20 HP, so this is theoretically a bit more. I think the hydro trans sucks up the difference, I really can't tell at a seat-of-the-pants level.
After 6+ months of near daily use and approaching 100 hours on the meter I have only two, very minor, complaints:
1. This is my first hydro tractor and the transmission noise, while normal, is aggravating in a closed cab. I just bought a good pair of earmuffs and keep them hanging on the loader joystick. Now that I'm in the habit of putting the muffs on before I even start the tractor, it's not a real issue, just different.
2. I had really hoped for more capacity on the loader. The numbers in the specifications are better than my JD was, but there is no noticeable difference from the seat. It'll pick up anything the JD would, but it falls short on some of the things I was hoping to be able to pick up with the forks. Again, not a real issue, just something that didn't work out as I'd hoped.
Feel free to PM me with any specific questions you may have.
Edit: Here's the thread I started on mine when it was brand new:
http://www.tractorbynet.com/forums/owning-operating/336007-first-impressions-new-kubota-b2650.html?highlight=B2650