I tend to agree that King does better with short stories (at least compared to his more recent novels). I think King has really good ideas for stories, but they must rarely be fleshed out enough for full novels so when he just does them in short form they really shine. The Jaunt is great.
Not that his novels are bad, in fact many are great. Just that they tend to be hit or miss IMO. The Dark Tower series suffered for it. The last two books were hot, hot garbage, although the very very ending I thought redeemed it a little (I know I must be in the minority in thinking that, but I thought it was perfect). I barely made it through the first book; books two and three were riveting; I HATED Wizard and Glass; Wolves of the Calla excellent; Song of Sussanah was among his worst ever, if not THE worst; and the Dark Tower just didn't satisfy aside from the ending we weren't supposed to read.
I also think he's not as good since his accident, I believe it took something out of him.