You touch on several points and one poster puts a personal taste thing into it. Okay, one thing at a time.
The accuracy guarantee has been on the Lee collet neck sizer die for maybe twenty years. Don't think they have had to pay off on it much.
Accuracy is dependant on a lot of things, some of them quite difficult for many to fully appreciate. One is a straight case neck with a proper inner neck diameter for concentric seating. Many people think a high "neck tension" is a good thing; it is not. I prefer the Lee collet neck die for both straight necks AND the correct neck diameter for factory rifles above any bushing type sizer and have the concenticity gage to demonstrate the difference.
That neck die has a moving part so it isn't the same, simple minded "push the case in, pull the case out" as others. Thus, it has a learning curve and a bit of mechanical apptitude helps. You have to develop a feel for it but it's worth the effort to learn to use correctly. It doesn't need case lube because there is no sliding case-to-die contact but don't try to use your FL die without lube or you will have one hard stuck case.
How many reloads you can get with it varies a lot by the actual diameter of your chamber neck, if it's tight you can get a lot or reuse. I anneal my necks after each 5-6 loadings and that allows me to easily get as many as 30 cycles per case in hot loadings and with very little case stretching in the process.
(Lee's "Dead Length" bullet seater dies work quite will IF the users follow the instructions correctly. Seems a lot of people don't bother with instuctions so it's not the dies fault if they get less than consistant results, is it?)
Some like one kind of lock rings, some another. That's fine but it's only personal taste. Lee's rings actually work fine IF used correctly but, like their collet neck sizers/seaters/bullet crimpers, they work differently from others. Some people like them a lot, if for no other reason than they allow a bit of softness in the die threads that can allow for better case alignment. Equating the value of the dies to a different taste in rings seems to be a bit off center. They aren't my first preference but I can work fine with them, they really don't make no difference to me. ??