Glen,
The 154 Lo-Boy is very similar to the 1x6/7 series in the same way the car companies make their compact vehicles similar in design to the big boys. Take a look at the early '60s Chevy IIs and compare them to the Impalas of the same era. For something a bit more recent, compare the looks of the late '80s Ford Rangers against their F-Series from that time frame.
Mechanically, the Lo-Boys were very similar to the old Farmall Cubs, sharing most of the engine and driveline components with them. They had some PTO issues, and horsepower-wise the 154 had less power than a 169 Cub Cadet. They were pretty good field mowers, but not great pullers.
Compared to Cubs, they didn't build that many of the Lo-boys, so getting parts could be pretty expensive and problematic.
A bit more on-topic, I got some stainless steel setscrews for my PTO. I couldn't find them in cone points, so I skewered the longer ones on my T-handle and twirled them on my grinder to make the tips conical.