I like Gerlitz Guitar Honey to clean and condition my fretboards!
The only issue I have with this product is that while they won't reveal the formula, they say it's "mineral oil based." Generally, mineral oils soften wood fibers if left on the wood to soak in, become more gooey, and attract more goo.
Folks put this stuff on, it looks all glistening and pretty, and think they've done themselves a good turn. But that may not be the case.
Sure, mineral oil makes wood look pretty, and it's great on cutting boards that are thick wood designed for a knife to dig into. But a guitar fingerboard isn't thick wood designed for knives, it's pretty thin wood and it should resist abrasion from strings scraping against it, fingernails, etc. That's why hard woods are chosen for the purpose in most cases - maple (usually finished), ebony (a heavy, naturally oily wood) and rosewood (again, oily and hard). But the natural oils in ebony and rosewood don't break down the wood fibers.
From what I've read over the years, mineral oils do.
So if you soften the fingerboard's wood fibers to make it look pretty, are you doing the guitar and its tone any favor?
I don't know for sure, so I stay away from stuff like this that isn't manufacturer-tested and recommended. Maybe it's fine, maybe it's not, but it's mostly a "feel good" thing and not something that really enhances the guitar.
YMMV.