Agreed. I rescued an HP Laserjet 4M+ fro the trash at work; was thrown out because the output rollers were old and not longer grabbing the paper very well, so paper was jamming there. An easy, temporary fix was to sand the rollers a little, bit I eventually bought a replacement roller kit for around $20, later bought new pickup rollers and a "NetDirect" LPD card. For maybe a total of around $40 and some elbow grease it's pretty much a new printer.
The 4M's are EVERYWHERE - I see them at banks, medical offices, and lots of other businesses. They last forever and supplies are VERY easy to find and affordable. The toner cartridge lasts a long time.
There is one issue with older HP's (the LJ4 series at least) that comes up: the infamous "Paper Size Error"; it's actually an easy fix.
The actual cause is related to a solenoid which hits a lever that momentarily halts the pickup roller mechanism's rotation, preventing it from feeding another sheet of paper too soon; this enforces an appropriate "gap" between consecutive sheets of paper. The lever has some felt on it as a cushion, but over time the felt deteriorates and gets sticky, and the solenoid sticks to it just long enough for the mechanism to do another, premature rotation, which causes an overlapping sheet of paper to get picked up, thereby confusing the printer into thinking it got fed a really long sheet, hence the "Paper Size Error". This happened to me, and it took me a while to figure it out; I had to run the printer with the left side exposed and observe the paper feed cycle. HP 's solution was bogus (forgot what it was). I just cleaned remnants of the old felt and stacked some clear tape on the lever; been working perfectly fine ever since, and I did this several years ago.
As long as you aren't afraid of opening up the left side of the printer, it's easy to find and fix the problem - I'd hate to see a great printer thrown out because of a little piece of felt!