Olivers are indeed sweet. My Grandpa has been collecting Olivers for a long time, and my Great Uncle restores and sells Olivers (Larry Harsin of Olivertractor.com). We've got bunches of these old girls sitting around, and we make a point of getting them out now and then to use them. It's great to hear these tractors work hard.
We've got a Super 55 gas that we use mostly on a little brush mower, a really neat little Airport 25, a couple of 60's, a couple 70's, 3 66's, 4 77's, a bunch of Super 88 diesel and gas, and my baby - a Super 99 with a GM 3-71 Diesel. There's a lot more than this, but that's what I could think of off the top of my head.