Hydrostat is so nice, and quite honestly pretty indestructible.
I am not a fan of anything at big box stores in this department. They are stamped steel, light duty, and are basically a push mower with a seat. My friend bought one from HD and when we loaded it in her truck, I was able to slide it left and right to get it centered. The thing was a featherweight. She couldn't get traction, it broke constantly, and the pulley for the mower deck belt was on a cheap flimsy steel bracket that kept bending and throwing the belt.
I bought a mid-70s Bolens HX14 for $500. It has a big, single-cylinder 14hp motor (forget who makes it, but with my luck it's a Tecumseh). Hydrostat. The rear axle on it is a massive chunk of cast iron. The frame rails are nearly 1/4" thick steel. It had no trouble towing my 19' bowrider in and out of the garage. Beefy piece.
If you only ever want to mow, get a cheapy and cross your fingers. It will mow. It won't be a heavy duty thing that you can use for things like plowing, hauling a trailer full of wood, or jockeying trailers. It will just mow, and it will do so for a few seasons.
I would buy THIS in a heartbeat.
I would also buy THIS really quick
Think older. 70s, 80s. Tractors aren't like cars. A good old tractor can run for thousands of hours. Dad and I have tractors that have been used every year since 1932 and I remember one needing a clutch and another needing a magneto. They don't have hour meters on them, but holy moly have they had a hard life. A new box-store tractor is for suburbia and it will last a few years mowing a dozen times a year.
Any John Deere that says Sabre, or the model number starts with a letter, pass. Anything that starts with a 3 is pay dirt. The 322 in my opinion is one of the finest lawn tractors ever made. It has a 3-cylinder Perkins engine that was originally designed as a 17hp diesel, but they changed the head design and made it a 22hp gas engine instead. It is a brick outhouse. 316/317 is another brilliant choice. Nothing wrong with the 1- and 2- series, but they're a little small, very long in the tooth, and hard to find hydrostat.