I've heard this about The Stand, I actually had a friend of mine FINALLY make it all the way through it after numerous attempts. I'm pretty sure I remember him saying he liked it, but it dragged on a LOT.
The only Stephen King book I've read was 11/22/63 and I thought that was really interesting. But definitely not enough to make me attempt The Stand, or any other of his books.
I really enjoyed 11/22/63 and read it three times (I think). The alternate endings/possibilities he presents at the close of the story (if the main character had done this or that - time-travel involved and I don't want to give the story away) are a good example of King's imagination at its best IMO. He's a flat-out insanely good writer when he is doing that.
I particularly enjoyed how he fully placed me into 1958 during the first few time-travel bits. He really captured that era. It's easy to see his nostalgia for the America of his boyhood since he has many stories where he takes you there. I also liked the fact that he leaves out all the really foul stuff in 11/22/63 that's included in many of his horror stories. Example: a man being raped with a handgun in THE STAND was so over-the-top and pointless that it almost made me give up the story at that point.
I find a lot of his novels very forgettable. I've read several that I've never thought of again after finishing them. He has a very faithful and forgiving audience. It seems to me that much of what he has written should've never been published, but he's a cash-cow for his publishers for sure.
His book ON WRITING is also very good - part memoir and part how-to for would-be writers. I think I've read it thrice as well.
On a personal level, I find his ranting and raving on social and political issues to be very much a turn-off, even when I might agree with them. I mean, really, who asked Stephen King to straighten everyone and everything out? Somewhere along the way he seems to have turned into one of those celebrities that knows better than the masses and feels the need to talk down to us from his pulpit. I wish he'd stick to the typewriter.