I stopped using drops and went back to spit mainly because of convenience. I thought I read somewhere that you weren't supposed to let it dry completely before rinsing; maybe I was wrong. Anyway, since I didn't want to let the drops dry completely, and since I didn't want to use my rough kevlar glove to spread it, it was inconvenient to work out the sequence of putting my gear on and getting into the water and also deal with the bottle of drops. I've found that if you do it right and don't rinse it all away, spit works just as good as the drops. Except...
I just got back from a long vacation in Belize, and for most of the trip I had the most frustrating problems with my mask leaking and fogging. I couldn't understand it because I never have that much trouble at home. What was I doing different?
I often go several days without shaving, so I didn't think my stubble was causing the leaks, but when I shaved the problem went away, so I figured that the difference was just a few extra days of stubble.
The fogging problem only went away when I went crazy on cleaning the inside of the mask. Fresh water was not that easy to come by in the super-cheap accommodations and camping we had, so I would let the mask go several dives without even a fresh water rinse. But when we had a hotel room I took the time to clean my mask properly, and it didn't fog after that (using spit).
Back to the original context of the thread, I never noticed that much difference in the performance of Sea Drops vs. Sea Gold, just in how goopy they are coming out of the bottle.