They pull with more authority than any factory 036's I own and have run. At least in the wood in these parts. I have a stock 361. Certainly faster chain speed in the smaller stuff but the 630's with gasket delete and modest advance start to show their nuts in the 20"+. Mean instead of scream. Get the appropriate era 61 carcasses and with an open-windowed Meteor, you can mix and match them for the next 50 years. So, yes, parts are readily available. Cranks, coils, bearings, seals, fw's, pumps and so on. In all honesty, saying they are easier to work on than anything German would be an understatement.
I pick up most all of my projects from the local free-and-under Smithrite. I could never justify dropping $800+ on a new 60cc saw, as I don't make a living in the forestry industry. I am a firewood/saw enthusiast that happens to rebuild pretty much any saw I can get my hands on. An equal saw opportunist, I am. I can appreciate a design that pushes 40 years old, sits well into the modernly equivalent 4 hp range and manages to put as much wood on the ground at the end of the day. Kinda disappointing that Stihl has had 35+ years and billions of fan dollars to come up with their latest design and they can only squeeze out .3 more hp in stock form than an old Jonsereds 630.
That's just me though.