The beams should be identical. It's my understanding that the light engine and reflector are the same, only the housing differs.
Besides the traditional vs anglehead differences, the clip is also different. The clip on the SC51 is extremely secure, where the clip on the H51 is a snap-on style clip. Both functional, but one is clearly more solid than the other just in case that matters to you.
Also, by having the switch on the side, the SC51 is more likely to turn on accidentally in your pocket, but you can lock out both lights by loosening the tailcap, so if you're okay with that, then accidental activation is a non-issue for both lights.
If you're looking for an EDC light, I would recommend the H51 over the SC51.
I purchased the SC51 to be my nightstand light. I consider an anglehead light like the H51 to be unsuitable as a nightstand light since it's so easy to blast yourself in the face since the orientation isn't obvious when you grab it. With a traditional light, there is no doubt at all which way the light is facing when you turn it on.
--flatline
