Based on your budget, I might still stick with older iron if you want to stay out of debt, and put the $$$ into attchments and a loader. The loaders may be slow, but they work, and there is no requirement that they come off; it's nice, but I'll bet that more than 50% of the folks with quick-remove loaders never take them off.
As to which old iron, in my opinion, you're best sticking with a Ford; there is at least one site on the internet which guarantee they stock every part for every Ford tractor ever made. I, too, recommend the 600 series or newer. I love the N series. I had a deposit on one before I came to my senses and bought a new tractor. But there are definite limitations in the way the PTO (power take-off) works.
But now, take everything I said and throw it out the window now that I know you have ~$5,000 and some possible room for stretch. That's exactly what I had when I set my priorities. I put $5K down payment on a new New Holland complete with a package of new attachments, and am paying off the balance over 36 months with 0% interest - same as cash, less than $300/month! You could get by with something as small as my TC18 as long as you are willing to take 4' wide cuts with the brush hog instead of 5' or 6'. Or, you can go bigger - your dealer will be as happy with a $5K deposit on a TC33D as on a TC18, for example - just a few bucks more per month.
Now, you have a modern tractor with safety features, loader, hydrostatic drive, 4WD, power steering, great hydrualics, proper 3PH, your choice of tires, and whatever attachments you want for your $5K, and have a warranty, a dealer that (hopefully) will fall all over himself to help you, and can get busy with the fun of using the tractor instead of repairing the tractor.
I use the New Holland only as an example (although I wouldn't have picked it if I didn't like it); you can do equally well with Kubota or John Deere, depending on your preferences and the dealers in your area. As for the Korean, Japanese and Chinese tractors not supplied by the big three, it's my observation that few of them come with hydrostatic drive and dealer service may be spotty, and the finance packages may not be as attractive. There are exceptions, but there must be some reason why the price is lower, right? They all use similar components from similar sources; even the "big 3". But, that doesn't mean you shouldn't consider them - just be aware that you may not be comparing oranges to oranges. You'll also get a lively debate on whether hydrostatic drive is better than gear drive (which is what's on most of the imports); all I can say is I love my hydro, although I did spend about 80 hours on a Caterpillar Power Shift loader in the last couple of weeks, and that's pretty neat, too - all electric clutch and shifting (for about $50K).