I agree. Though I really didn't enjoy Gerald's Game, I really did love Insomnia and I just finished 11/22/63 and, though I found it to be a great deal outside of his usual writing style - not as creepy - I did enjoy reading it.
Books, much like music, television and movies, are many times a matter of personal taste. You can say you didn't enjoy a song, but still credit the artists with talent. The same goes for the superb talent of Stephen King. You may not enjoy all of his writing, but you have a personal vendetta or no literary knowledge if you claim he is talentless.
Have you re-read Gerald's Game? Sometimes a re-read proves beneficial, I did that with From A Buick 8 which I didn't care for on the first read but on the re-read I realized how great it really was. It may not work for you but I always suggest that if someone doesn't like a book on the first read through.