As everyone has already said, depending on how much you have to mow and how quickly you want to mow it, size your tractor to fit that and your budget. I've only got 22 acres of mostly open farm land that is currently leased out but I've got almost 2000' ft of road frontage on 3 different highways that I want to maintain and about 3 acres of woods land that I want to thin out and keep grassed and maintained. I tried an Iseki with a 4' mower but the tractor is too small and mowing ditchbanks is tough and dangerous because of the slope. Then I bought a FarmTrac 60 and put a MicroMower on that but mowing 3' strips takes too long. I sold the FarmTrac for cash and carpentry work for more than I had in it and came across an 07 John Deere 4120 with loader that had been repoed. Only had 650 hrs on it and looks like brand new, except for the bucket but I financed it with nothing down at $400 a month and I'm adding a 6' rotary mower (bush hog type). The 4120 is 4WD and E-Hydro drive (2 ft pedals, 1 fwd and 1 reverse). The dealer delivered it 35 miles. The fuel guage quit and the dealer is picking it up in the morning and replacing the guage as well as checking it out to be sure he also fixes what killed the guage, and then delivering it back, all at no charge. The tractor is rated at 43.1 hp with 35 hp on the PTO and will easily handle everything I want it to do. In my area, all of the full time farmers have John Deeres and there are dealers as close as 10 miles from me and service from all of them is excellent.
The tractor only weighs about 4000 lbs so any 2 axle trailer will transport it.
The 4120 is also the only so called compact tractor that does not have a foreign made engine. This one has 4 cyl engine made by John Deere, not the 3 cyl YanMar engine.
Anyhow, if cost is a consideration, consider a new or fairly new tractor, such as a John Deere, though there are others, because there won't be much maintenance to do on them and you can finance them easily. I'd personally rather pay the money for the newer tractor than pay it out in repairs, where you'd also have down time and labor costs and/or even your own labor.
BTW - Replacement bearings on the MicroMower from the manufacturer cost me $79.00 each but the same bearings from John Deere cost me $29.00 for the pair and may have been even cheaper at NAPA as they are standard Timken bearings. (They are one of the few parts at John Deere that don't come painted green..;-) )