I do not know too much about the mowers you are pricing since I have much of my experience with John Deere. I paid $1850 for my Mower in '07.
I can only speak for what I own...that said, you want to size the mower to the tractor's PTO rating/Side Skirts should be at min. 1/4" thick (takes a lot of beating)/Upper deck a min. of 1/8" steel/Rotation (per owners manual: 540/14,347ft/min).
Make sure you keep your blades sharp and your mowing deck properly adjusted.
Your deck should be slightly lower in front so you are not double cutting the grass...as for sharpening, I have developed my own way of doing things. *Make sure deck is supported before removing blades.(MX5 Wt. 728lbs.) To Remove disconnect PTO from tractor, look in inspection/access cover on top of mower, and remove blade nuts...I use an impact wrench with long extention. Once removed, I use a 1/4 grinder to reshape and hone up the cutting edges. Now here is where it gets tricky. YOU WANT TO MAKE SURE THE BLADES ARE BALANCED OR YOU WILL THINK YOU ARE IN A BLENDER WHEN YOU ENGAGE THE PTO) I keep my blades balanced very simply. I have a 2ft. piece of 2x2 wood with several staples set to hold a round bolt or??? I use my Phillips Screwdriver. I place the block in a vice and level it so the two staples are facing up and away from the vice. Insert the bar or (my case) the screwdriver through the staples so the handle just hangs off the end. I then have a piece of 1/2" rebar 24" long. I ground a small indentation in the center and use this as a reference pt for center. When you place it on the bar, the rebar should be balanced.
Take the two blades and hang each simultaniously on each end of the rebar. If one blade goes lower than the other, you know that is heavier and more grinding has to be done to it. \ This is a fail proof way of doing it and has worked every time I have done it.
Good Luck