The soundstage was perceivably larger with the EPH-100 mainly due to the presentation having more bass emphasis and thus a slightly more recessed midrange when compared directly to the RE-400, but realistically they are on par I'd say, a bit above average in size. While I don't listen to much classical (I just have a few select baroque pieces), I think the imaging/separation is a bit better on the RE-400 and it will feel a bit less congested, so better suited for classical. I do have a good bit of modern piano, acoustic and vocal tracks and I feel the RE-400 is definitely better suited to those - they have a special way with vocals particularly (more upper mids presence perhaps, transparency in mids), enough to warrant me having a pair on hand still. They're both pretty versatile, but the RE-400 presentation is relatively non fatiguing and as a result could be considered more relaxed, whereas the EPH-100 is a more exciting experience and definitely better suited to rock, metal and electronic genres. I'd say technically speaking, both are equals with different tuning and presentations, but I'd recommend the RE-400 for the genres you listen to most...and I think they're still quite decent with rock. If after trying them you find yourself wanting a bit more warmth/bass and a bit of added lushness in the lower mids, you can't go wrong with the EPH-100 there. I will say there is a bit more tweakability in regards to the RE-400 in that you can add additional damping material in the nozzle (essentially a low-pass filter to bring everything below 1kHz more forward) and there is a wider assortment of tips that work with them.
Edited by modulor - 5/1/14 at 9:20am