I am by no means an expert, just a casual fighting game fan. After using both, I have to give my vote to LS-32. Note that I’ve been using the JLF (Sanwa) on my HRAP1 for about 4 years, though about 1 month of intensive use since the beginning of this year, and only 1 month on the LS.
Single motion moves are a lot easier for me to pull off, even 360s and SNK’s complicated supers (QCB>HCF). Though I find it much easier to pull off double QCFs on Sanwa since there’s a lot more room to do corner circles (maybe i’m still transitioning to Seimitsu).
Charge moves are a lot quicker and effortless to pull off, mainly due to the shorter shaft. My main problem using Sanwa for charge moves are with d>uf/ub (Claw’s specials) and with Horizontal Supers. Mainly because of the amount of effort it takes to move the stick and probability of hitting the wrong direction. Both problems are solved when I switched to Seimitsu. Though incidentally, Vertical Supers, almost effortless on the Sanwa, comes off as Horizontal Supers half of the time on Seimitsu.
It comes down to preference. I’d suggest you try them both before deciding. For someone who’s transitioning from Sanwa, it can be a difficult process due to the need to de-emphasize movements (with HCFs sometimes, my muscle memory is trained to do a bigger HCF from using Sanwa).
But once I’ve gotten used to the Seimitsu stick, it feels like I’m getting better control over movements. A HCF feels like a HCF. With Sanwa, sometimes feels like you’re just flicking air because of its looseness (though in all fairness, after 4 years, the spring might need change).
Pros of LS-32
Tighter spring (“feeling” of more control)
Shorter throw (less distance to execute moves)
Shorter throw (equates to minuscule movements that might affect accuracy (eg. complicated small movements like double QCFs); I’d imagine someone with larger hands might have difficulty)
No official octagon gate
I’m no expert on the technical side of things. But in conclusion, because I’m getting better controls (I’m not afraid to pull off DMs in KOF now with Seimitsu!), I’m not going back to Sanwa.
Note: the games I’m mostly playing on are Super SFII Turbo and KOF '98, both which generally have unforgiving inputs.