Threaded inserts are the whip. I've got them on a couple guitars now, and intend to do the next one as soon as I can get into the basement again. The neck is held on tighter because you can use finer-threaded screws, so you get a better neck/body connection than a standard bolt-on, and definitely better than a glue-up. Plus, it makes it easy to pull the neck off whenever you want without worrying about tearing up the neck mounting holes. Word is the tone is much better, but I can't speak to that since I've always started with inserts so I don't have an A/B comparison on a given instrument.