Trouble is you are not the first to go here and the supply got run down about 6 or so years ago with this boom in the retro PC lark. Parallel ports stuck around for a while in a lot of things (business and tech users still wanted them), even more so if you find a docking station -- my docking station for a core2 era DDR2 sporting Dell laptop I was still using as my main machine last week and for years prior has one. That also places you comfortably in SATA hdd territory so SSDs are easy to source (IDE SSD or CF is... not fun), though be sure to find out about the TRIM commands. You might also get lucky there and have a GPU of some merit (though do check recalls, lawsuits and general failures here) where before most things would be Intel, maybe Via way back in the day (so basically as good as intel) and not much else saving the CAD desktop replacement workstation things that will be a fortune today. Alternatively on the GPU front you can potentially go in for the external graphics card stuff (people took to ripping out the wifi card and as it is PCI or some flavour you can get a slow take on a desktop graphics card if you are so inclined).
Still IBM's business laptops of the time were pretty sweet. While Lenovo has since done all it can to piss the reputation away this was what made them not a household name but the go to option for a lot of businesses.
If you have pockets deep enough for a vintage toughbook then by all means.
Depending upon what you do you could also find yourself with a laptop with a nice amount of screen resolution.
Basically it is the same as today. If it is the business, rugged, workstation or super high end business line of laptops from a major vendor it is probably good stuff, built to last and spare parts are also a thing, not to mention a nice docking station is usually on the cards. If it has otherwise decent specs and an unknown vendor you might get something going on. If it is a consumer level or worse from a known brand it is probably trash, and if it is an unknown brand and mediocre specs it is almost certainly flimsy super trash. Most of the major players in the 98-2000 era are still major players today (the IBM-Lenovo being the main change, the rise of Sony is a thing but that just means you won't find anything and the more recent move to semi obscurity of Fujitsu (Siemens) even if they still play is a thing I guess).