There was an article in a well known Consumer magazing (page 65 Oct. 2000 issue). That asks
<< Is Windows Me for you? >>
. Basically, it states that Me boots a few seconds faster than 98 unless you're running a 1GHz Athlon. It was 10% slower than 98 at routine work. But it's supposed to be more stable (something they weren't able to test). It's Multimedia, Home Networking, and Enhanced Internet are items you can download free from Microsoft and work with W98.
It also mentions what others have already pointed out. That any upgrade can bring unanticipated problems and frustrations, such as resolving a conflict between Me and hardware or software you already use.