John F, I guess it really depends on what you can spend on a tractor and what type of mechanical abilities you have.
My experience with an old (1949) Ford 8N has been sour and sweet. It started on 12 acres and is now cleaning up and maintaining 40. I have had it for 14 years. The first year was a bit hard as the oil pressure dropped it's first summer and I had to sink rebuild money into it, BUT since then it has been a wonderful piece. Short story is... I ended up with a 4 to 5 thousand dollar investment (Used Brush Hog and Blade included) and it has been wonderful since. Old rule of thumb with antique tractors is that you will spend an hour working on the tractor for every 10 to 20 hours using the tractor to do work. Sometimes it's just 30 minutes making adjustments, other times it's a weekend repairing major worn out stuff.
Some folks get lucky and by an old rusty tractor at a low price that gives them many hours of moderately trouble free use, but it's a roll of the dice.
The flip side is one could add a bit of money to that and get a new china made outfit with some modern technologies and get many years of low to no tinkering use so long as you don't over exert it and break a big part.
