By the way, SD cards over 32Gb definitely increase boot time.I compared the difference side-by-side with ninjhax payload and this one on two N3DS-XL. Both units have fw9.2 and uhs-1 sd cards from the same manufacturer (32gb and 64gb). The speed gain is negligible. The new payload loads the "corrupt" image ~1sec slower, but boots ctrboot for around ~0.5sec faster.
Don't know about stability, because the old payload did already work for almost all tries. No numbers here, I didnt make a statistics for it.