I have been using but sauce for about 10 uears. Previously on all of my solid body electrics and now on my Martin acoustic. I no longer play solid body electrics at all, I sold all of them and the gear with them. I have been using the same tube of nut sauce for about 6 years. It keeps my strings from grinding on my guitars custom bone nut. There is no pinging noise when I tune. I use it at every string change. I do agree a much thinner applicator would be nice. I use a piece of floral wire that my wife gave me for applying the sauce in my nut slots and it works perfectly, it fits in even my high e string slot. You can get this at Wal-Mart in the craft section very cheap. I highly recommend this product, especially for bone nuts or any acoustic.
ProsStops excess wear on the bone nut on my Martin acoustic. Also stops that pinging sound you hear when tuning. That sound more often than not is your strings sticking at the nut. Also a tube lasts a very long time. I'm on my 6th year and still have plenty left.
ConsYes a smaller or thinner applicator would be nice but, the floral wire I mentioned above works great, it's cheap and easy to find.