Thanks, I'll probably check out the respective threads. I'm not a huge fan of modding though, so I may lean towards getting the SRH840. One last question: I generally don't amp either. Are these low-impedence enough that I can just play them with my laptop and/or mobile device?
The KRK requires less modding than the Shure, only a cable replacement. The Shure might need a softer headband.
Both will sound fine from your sources, with the KRK a little easier to drive from an iPod or phone. The Shure will improve more with amping than the KRK.
Best luck with whichever you choose.