Spelljammer was/is awesome. As creative, really, as Dark Sun, but in a more deliberately "fun" direction.
It's confusing as to why it's got all the hate. Lots of people don't like Dragonlance but they rarely turn up to post about how it was dumb/stupid/etc.
I think there is still a drive among some gamers to insist that the hobby must be "serious". "We're saving the world!" "No fooling around!" etc. etc.
(the Spelljammer novels went this route, it was actually painful to read about this mopey protagonist wandering around)
It is, however, also one of the most challenging settings for a DM to run.
Why?
Because, usually, the players get a ship. And once they get a ship?
You can go anywhere, and do anything you want to.
So either the DM really works with the players or it gets 'rail-roady'.
As a setting it is fantastic, and you should definitely look at the Spider Moon Polyhedron. The author (Andy Collins IIRC) has more stuff on his website.