I am looking at a 2100 and it looks almost new. The only thing about it is the compression. The fellow says it has 120 psi compression and this seems a little low to me for that type of saw.
120psi is acceptable, but on the low end of the scale. Pull the muffler and take a look if you are serious about purchasing it. Finding a problem at that point may help with bartering the price a bit.....Cliff