I know JMS' run on Spidey was pretty long - was it about a 100 issues or so?
Pretty much. JMS did 74 issues of Amazing Spider-man, but he also wrote some issues Sensational Spider-man and Friendly Neighborhood Spider-man during crossovers (such as "One More Day").
I have been reading some of his run in the graphic novels format. Just read both One More Day (finally) and reread some of the earlier stuff with Peter and MJ finally meeting and resuming the marriage (The Life and Death of Spiders and Till the Stars turn cold). While there are several things that I don't quite agree with in JMS' run - the organic webshooters. I wasn't a big fan of the spider-totem storylines also tho' I liked both Ezekiel and Morlun which are both corner-stones of the spider-totem storylines. But his writing made it all fairly engrossing.
I would be quite interested in reading about how he treats WW's more mythological side (rather that Diana Prince, Ambassador of Themyscira - which was done enjoyably, I thought, by others before him). I have been a bit negative on the whole Superman thing for a while now. The idea of New Krypton doesn't really interest me. But hopefully he will be the only Superman around by the time we get to JMS.