Picked up an IBM Aptiva system recently, and will have to do a clean-installation to clear out the remnants of some sort of infestation (Windows as a whole is being temperamental, and there are torrenting applications installed).

I've used Autopatcher successfully in the past, but how does this (now-discontinued) packaged stack up against the more recent "Un-Official Service Packs" developed for Windows 98?

It's the last one to have the fixes independently (fix-by-fix) installed. The Unofficial SP seems to be pretty good (built like an SP) and has (some) more recent fixes.

Best bet - try them all and decide for yourself. What you find here will probably be the best that can be found on the WWW bar none.

The links are here, so go for it. The hardest part (AFAIK) will be the drivers for that beast.

Drivers were a bit of an effort, although the system is based around in i440BX/ZX chipset (on either an Acer or AOpen motherboard), ESS sound solution and Number-Nine (Really S3) graphics. I seem to have found the correct drivers, although haven't yet gotten around to reinstalling Windows. I gave up on archived drivers from IBM quite quickly, and initially thought Intel had pulled the 440 Chipset INFs - although it turns out they call it a "400-series chipset" these days.

Fingers crossed this all works. I haven't found a source for the original IBM software, and was initially going to use a Direct-Cable-Connection to accomplish a transfer. Then I realised the system was probably still victim to a trojan infestation of some sort (judging by entries in MSCONFIG) and thus elected against doing that.