A dairy farmer I worked for as a college kid back in the '60s liked Ollies. I spent a lot of time on a Super 88 gasser and a 770 diesel. At the time they seemed to be big, tough, reliable, well made machines. Seldom gave any trouble and were used hard every day. Both had 6 cylinder engines which, I believe, were made by GM. Think I saw the 88 the other day; fully restored by the guy's son-in-law....sweet.
The 1800, if I'm not mistaken, is from the late 60s or early 70s. It's bigger than any I have experience with. There seem to be a lot of that vintage in regular use in this area. Not sure where they get their parts.
I always thought of the Ollies as somewhat upscale from contemporary JDs and Farmalls. They had a single shifter 6x2 transmission with a maze like shift pattern. It worked well and was an improvement over what the old JDs & Farmalls offered. Not sure what the 1800 used. Back then as an operator I always preferred Ollies over anything else and still have a soft spot for the big old beasts.
If you need the power, a good 1800 diesel might be a fine choice. If it's a gasser, it'll probably eat you out of house and home.
Bob