If i recall, MTD makes most to the tractors you'll find - craftsman, Troy-built, Cub Cadet and Yard Machines. They also make the entry level John Deer, I think. JD still makes the higher end models. Husqvarna makes their own.
If you're talking sub $1,000, chances are pretty good every thing you're looking at came out of the same factory. The one thing that will make them all last 20 years is regular maintenance. Rather than what brand, here are some things (besides a cup holder) I might look for:
1. Greater than 17 hp. Preferably >20 hp. Kohler and Briggs&Stratton I/C are solid engines and will last forever when properly cared for. A V-twin engine is awesome.
2. Whichever you buy, make sure it has an oil filter. Your oil and your engine will last longer.
3. At least a 42" deck. Anything smaller and you might as well push mow.
If I could get anything, it would probably be a John Deere or Husqvarna zero turn, 25+hp, 54" deck.
Oh, one more thing - there's a lawn mower guy on Rt 114 in Lewisberry (Space Highway). He may have what you need to keep your mower going another 5-10 years. You can't miss the place - front yard is littered with tractors.