I use Scruff and Grindr. I like them for different reasons, which is funny considering they're both essentially hook up apps. I don't know if their use in LA is representative, but generally I find Scruff to be "saner" like the poster above. Guys generally seem nicer, friendlier, more down to earth. It's a better experience for flirting, and the app itself has better features than Grindr despite being cheaper (or, rather Grindr's premium subscription is hilariously and prohibitively overpriced). Scruff seems more "long game" inclined - I've definitely had quickies from it, but generally guys are less pushy than they are on Grindr.
Grindr, at least in LA, seems much more "right now." There's an ENORMOUS amount of fake/scam profiles - almost all of which you can smell from a mile away, but Grindr doesn't seem to have any sort of filter for that stuff. The features on the app are pretty lackluster; there are features they consider premium that literally all other apps consider standard. What I find oddest is that despite being very limited in terms of what you can say in your profile (literally, character count) I'd say 2/3 of guys don't even look at them. I'm guessing my pics and basic stats are what seem to get guys attention; the number of times I get hit up asking if I'll top somebody or if I p N p - my profile is very explicitly "I am a bottom" and "absolutely no" is astounding. Meanwhile my Scruff profile is more descriptive and longer and guys seem to read it. The conversations there tend to be very superficial.
They irony is that 2 of my favorite fuckbuds, one of which I'll be seeing as soon as I'm in the clear since my vaccine shot, I met on Grindr.
When I travel (or rather back when I used to in the Before Times) I seem to recall Scruff being more useful than Grindr, at least in NYC and LV. I'd use both, but Scruff would actually deliver. Not literally but OMG that would be awesome if Scruff delivered. Anyway, my last trip to NYC right before Covid hit the guys who came to my hotel to fuck my brains out were from Scruff, and same for my trip to Vegas a few months before. So maybe the dynamic is different in LA.