For a while I've had a dusty 50mm f.1.8 Ai sitting in a box. I picked it up from a rummage box at a camera fair for pretty much nothing as the grease in the helicoid had gone bad - it wasn't stiff, more like dry and loose. Anyway, I've usually used my 55mm Micro AIS as a long standard, so never really needed another 50mm. Finding a few spare hours one cold evening I thought I might have a go at at service attempt. I had no repair manual so went into it blind. What a joy to work on it was. It was really beautifully designed. It was amazingly simple, not in a cheap way, but in an elegant way. The precision with which everything fitted together and articulated was beautiful. It actually looked like it was built to be serviced too, not sealed forever and forgotten. My only mistake was not noting how many turns on each helicoid before separation which meant a few goes to get it to focus to infinity. Anyway, helicoid was re-greased, everything cleaned and re-assembled and I now have a fully functional 50mm standard. I've been into a few FMs and FM2s as well and found the same thing, simple, elegant, precise. Going into an OM1 always fills me with dread in comparison, that's more like working on a watch...