Other credentials/certifications in the fitness industry? I haven't done it but I hear precision nutrition is decent. Besides that, I don't know of any. I was certified by ACE from 2006-2010, and NSCA from 2008-2017, and both were a waste of time. I kept the NSCA so long on the chance I'd need it for employment at some future point, but just couldn't justify wasting my time and money anymore.
If I ever do need it again, I'll take the damn test again, and also be really disappointed that I let myself get into such a position.
I've had a USAW cert since 2010, it's still current, but even at the time I took it, when I knew much less than I do now, I didn't learn anything by taking the course. It just checked a box. I picked up a few useful cues from the guys who happened to be assistant coaching that weekend, but some of the other assistant coaches were beyond useless. One of them was - I'm sadly not kidding - the 17 year old son of the guy in charge of the host facility. But the point is, the actual course material itself was super basic, and they practically gave you the answers to the test so that anyone who paid, showed up, and had a heartbeat would pass. I've taken other courses and cert weekends, but haven't found any nor do I know of any that attempt any kind of systematic, first principles analysis of the kind that SS does. Some specialty courses are useful if you want to know more about that specialty, but they still basically give the cert to anyone who shows up (or there's some kind of fitness test, which is not the same as coaching competency - i.e. the RKC snatch test doesn't tell someone whether you can coach the movements, only that you yourself are fit enough to pass the test).
I've heard precision nutrition is pretty good, though not sure if that qualifies as "fitness," and I haven't taken it myself to know personally.
I don't know our exact passing rate, but I think it's something like 15%. It would be lower if we still tested everybody, but you have to opt-in to be evaluated as a coach, so that ~15% is only evaluating those who think they have a chance of passing. It's not rocket science, but it does require both practical competency and theoretical knowledge that you can't obtain from scratch in a weekend course, or even in a few months.
That isn't to say there aren't other individuals or organizations to learn anything from about lifting. Like RTS and programming for advanced lifters, for example.
And it's also not to say that the SSC tests and evaluates for everything one could possibly know in the fitness realm. You couldn't use the SSC to justify getting hired as a pilates instructor, or running coach. Hell, it doesn't even evaluate for programming for advanced lifters. Just that I don't know of any other certification that, if you hold it, actually demonstrates a solid level of competency in the specific purview of what that cert is supposed to evaluate. In the case of the SSC, that purview is:
* The ability to teach anyone how to properly perform the basic barbell exercises in accordance with the SS model, and understand when a deviation from the model is required because of a special circumstance and adjust accordingly (can't get into low bar position due to shoulders; shouldn't clean bc of age or a specific issue, etc).
* The ability to determine the correct starting weight for each exercise (which can be less than the empty bar for some special populations), and then program the person effectively to do a proper LP from there.
* The ability to finish out the LP, extending it to the extent it can be, while continuing to improve technique as you go, and not allowing it to degrade beyond acceptability when the weights get heavy.
* The ability to successfully transition a lifter into the first stage of early intermediate training.
* The ability to explain, satisfactorily and in detail, the reasons why we teach the lifts the way we do and program for novices the way we do.
So the purview is limited, but within that purview, we're the only fitness cert I know of that does a really good job of ensuring that the credential means competence at the things it's supposed to. No one is perfect, and we've refined the process over time so fewer and fewer slip through the cracks. And many SSCs have expertise outside the purview of the cert, like Robert Santana or Feigenbaum are nutrition guys, along with some others. Feigenbaum and Reynolds and Baker may have different approaches, but they've all coached many lifters well beyond the early intermediate stage. Hell, so have I.
The point is that the SSC doesn't evaluate for those things, but does a really good job at identifying competency at the things it does evaluate for.