As stated, late 90's/early 2000 models were prone to dying early deaths. Lean conditions, tolerances wrong and a lot of operator error caused issues. The main error many boaters caused themselves was not letting the engine warm completely before going WOT. Tournament guys were blowing them left and right with their style of start/floor it immediately. The processor wasn't flowing fuel properly and they would go lean and then POW they'd go bye-bye. Also as stated, most other makers had issues as well.
If the engine has been well cared for and maintained properly and you are a careful driver, it could be OK but if you had a choice, I'd look for something after 2003 or later.
As far as service goes, you'll get nothing from Merc now on an older outboard. They've washed their hands if it's out of warranty.
UFM82