I enjoyed Cell. I'm quite the zombie fan anyway (although they don't seem to like me in return and bother my dreams every month) so the Phone Crazies were like uber-zombies, very cool. It seemed like a return to King's gory, fast-paced horror, which I enjoyed. As to the open ending, well, I've said this many times around here now, but I didn't mind it. It leaves it open for us to decide whether Clay's son was returned to him or not. If we're hopeful, we imagine that he did, but there's always a part of us that thinks perhaps he wasn't, which creates an unsettled feeling that goes beyond the end of the book (which is something that good horror should strive for, I think). Again with not finding out what caused the Pulse - we'll never know, and that's rather an uncomfortable thought. Plus King's books often have a good sense of realism (looking past the ghosts, zombies, vampires, and monsters here; but then, even these are often portrayed in a horrifying believable manner) and just how believable is it for our small group that the book follows to stumble across the source of the Pulse? I'm sure King could have written something plausible if he wanted to, but it would have had to be quite a coincide, I think.
As to Lisey's Story; I enjoyed that book, too. I admit it took longer to get into than other King books, but once I did I thought it a very moving novel. It had a tone that was unlike other King books, but nonetheless was still very good. And the private language; well, it was slightly grating sometimes, but I think it just added to sowing the closeness of Scott and Lisey's marriage. Couples who have been together for some time tend to pick up their own little habits and quirks.