Ryan for us ...... We had to disconnect the "low oil warning" feature(simply unhook the wire) because as soon as you would be on any kind of small slope it would automatically shut down. Other than that it's been a fine machine.
I have 2 ryans, one is from 1960 and I still use it all the time, They don't make that model anymore. It cuts a 12" wide path and is great in smaller areas. The other one cuts an 18" path. Both are great.
Some models I would consider :
I have a Ryan that I picked up for $700 with only 6 hrs on it, of which, 2 hrs were my rental. The place I rented from was going out of business, had the cash on hand, got the machine.
I saw the BillyGoat version at a trade show last month. What impressed me was the compact size and it wasn't top heavy like the Ryan. Something to consider if you work on hills.
Blue bird- Easy to use, and all wheel drive. Also get a -sod kicker thay work great for small jobs. Purchased a new Bluebird sod cutter in 2003. Priceless!!!!!!!!!!! .Try renting different brands, Find out what works best for you. For us it was- BLUEBIRD.