sliceoflife
ArboristSite Operative
Its not very safe, but I use a recent reincarnation of an 070. It will easily handle a 30" bar and is almost warmed up by the time I've finished blocking a dozen large Auzzie hardwood logs. Although I haven't needed many, there are plenty of new spares available (in various qualities) at very reasonable prices.
I've got a copy 070 I mill with a bit. Had to buck firewood for my FIL with it a month or two ago because my lil Homelite carb was wonky and it died on me after 5 minutes... it was exhausting. Keep in mind it weighs about TWICE what some of the other saws being considered do.
I would not recommend a saw that heavy for much other than milling or maybe felling massive trees?
WRT to older saws... as someone who has bought a bunch of older saws lately... I'd look at one thing before even considering an older saw... parts availability. Go to eBay/google shopping tab and see if there's a bunch of XL 903 compatible parts listed... any important parts missing from the results?