Okay, here's my contribution:
I have miserable nails too--always splitting or chipping. I've now been applying Hoofmaker for four months--I do it very faithfully, at least twice a day--and I think I'm seeing some improvement, but it's not exactly stupendous. My last nail breakage was about two weeks ago, which is just about how long I usually go between nail problems.
But here's an aspect that I don't think has been raised--a couple of months ago I started "ramping" my fingernails in what is now becoming a popular fashion. That is, instead of shaping the nail to conform more or less to the finger tip, I shape them so that they are very short on the left side ("left" if you have your hand in front of you, backside up) and rise more or less in a straight line to be longest at the right border.
For one thing, I do think this gives me a better, smoother sound (there are threads on this forum on ramping), but most important: now, when I break a nail, it always seems to break, naturally enough, at the place where the nail sticks out the most and is most likely to get in the way of foreign objects. And that, thank goodness, is now on the extreme right, which is the least important part of the nail for playing. So the last several nail breakages I've had really haven't gotten in the way of my guitar-playing. This is a wonderful, unanticipated consequence of ramping, and I urge all you others who also have wimpy nails to think about giving it a try.