I've got a Janome 634D overlocker, I've had it for years, (and think it was the top of the range at the time). So long in fact that there was no internet around on which somebody could tell me that it was difficult to thread. In those dim & distant days we looked at the instruction book and got on with it
It's sewn everything from rolled hems on silk chiffon to polar fleece and I rarely change a setting apart from stitch length, I change the needles to suit the fabric, the knife blades when necessary and oil it after every project . It's still going strong and I would miss it dreadfully if it died.
I still have the instructional VHS tape that came with it, no use to me as we didn't have a player until much later.