The Riflespeed is not low profile due to the straight gas tube design. I dunno, maybe it qualifies as such but I've had to modify/clearance two different hand guard brands to run the Riflespeed. The Superlative Arms and JP are lower with a bent gas tube design.
With that said, the SA is my preference over the JP as it's one screw to regulate gas flow, one that has detents so no need to lock it down. The JP has a gas flow screw AND a locking screw. I liked the idea of a side adjustment on the JP, easier to access under long hand guards (if the slot in the hand guard is in the right place) but you're still trying to find a tiny screw through the front with a long Allen wrench to lock the adjustment in place. If not covered by the hand guard, it's a non issue.
The SA is a bit finicky from the standpoint that there A LOT of "clicks" and rotations and you can accidentally go into bleed mode if you loose track. But once set, you're good to go. They claim it won't carbon lock but if you don't turn it periodically, it'll lock up pretty good. Can't comment on whether the bleed mode is something that's beneficial or not, I didn't dive into it enough to really form an opinion one way or the other. But with the fine adjustment increments, you can really dial it in.
On something like the Riflespeed, it may necessitate changing out the plunger to get you in the right range depending on what you're shooting. For 300 blackout, subs and supers, you'll want to make sure the plunger allows for both within the 12 allotted clicks in the adjustment range without having to go to the 2nd notch. A little hard to explain if you haven't used it but you can push the collar in and get another 12 clicks of adjustment. Just hard to do in the field if you're going back and forth between supers and subs. So ideally you want one adjustment range of 12 clicks to cover both supers and subs. It comes with two plungers and you may need to purchase others depending on what caliber you're using. I had to purchase an additional plunger for 300 blackout on an 8.5" barrel.
Additionally, you want to keep it lubed and it can be easy to compress the wave washer too much or otherwise damage it. I found that it would become locked up and hard to turn after firing a few rounds. I didn't have much of the adjustment collar sticking out beyond the hand guard which didn't help. The collar is also metal so it will get hot after firing a lot of rounds through the rifle. Still beats trying to find the adjustment screw with a long Allen wrench.
Wildcard entry, the POF Dictator gas block. If you have a setup that allows you to run it, it's superb and by far the easiest to use and adjust on the fly. It's also a straight tube design so maybe doesn't qualify as low profile. It doesn't have any of the downsides of the others but again, it's designed for a very specific setup.
