There is a 880 for half the cost of new in Ohio on CL right now. Look it over to see if it passes inspection.
I had several 066 660 084 3120 stock and modded. Here is what I am getting at. Depends on how much you use the saw and for what type of cutting.
I like the build of the 084 088 880 over the 3120 personally for a work saw. I also like the 3120's too, just some things I prefer on stihl.
There was a guy I knew running stock 660's rip cutting hardwoods with way to long of bar IMO. He said he had burned 2-3 of them going by dealers instructions on set up.
I sold him a woods ported 084, set it up where it was 4 stroking out of cut and cleared up in cuts and run 32:1. Feed back I got was the saw was ripping with a 50" plus bar and ended his problems.
I think his 660 problems IMO dealer instructions and not knowing how to tune your own eq, running 50:1 , 40" plus bar ripping hardwoods, carb was probably set from dealer with stops to run right at max rpm.