My first LandPride was a 1560 and I tore it up. Total abuse. Now even my dealer was impressed

This was due to beating it hard in an orchard. The 15 series is the "light duty" version and weighs about 500 pounds. The 18 series is the "Medium" version. It has additional welds that help the deck put up with the every day torture (hitting trees, etc) that I give it.
There is a "Heavy duty" version for commercial guys, and they really mean it. In vineyard land out here the growers will use the rotary cutters or a rototiller for extended periods of times. These guys weigh like 900 pounds vs. 600. They also cost $2000 and up. My local dealer has a 36" rototiller, HD, that he sells for over $2500 and can't keep them in stock! The average person in the USA uses a rototiller for less then 8 hours per year. This is why I have an ugly looking but functional Agrc. All I need. The HD guys are used 30-40 hours for weeks on end.
Back to the RC1860-it is medium duty and just a terrific mower deck! Get it with a clutch.