I don't have any maths for Horridon's, although I'd be willing to do it if someone can give me some stats to figure out how worth the stacking component is. One thing I would say is that the SoO trinket is certainly a lot more consistent, so you'll always get around the 1250 mp5 (normal mode) mark plus the bonus int, where as Horridon's has a tenancy of procing 8 times in a row before you've even got a chance to use any regen cooldowns, which can get a little tedious, although less annoying once you replace the Valor trinket.