Thought I'd chip in with my first ever post, I might have missed the bus on this thread but as it is a subject close to my heart I thought I'd contribute anyway.
I run (or ran) regular half marathons, injuries are limiting my mileage these days but I have owned a great deal of IEMS, the major consideration in my case is whether they can withstand the moisture (sweat) that can gather in your ears while running, foam tips help by soaking up the moisture but they have not saved some IEMS from permanent damage, the worst offender is unfortuantelty the best sounding one the DBA-02, my first set developed distorted bass after my very first outing with them, the replacements took months to arrive and have just developed the same fault and this was after a modest 3 miles jog, the other set to have failed on me were the Westone 3s, but I don't care much for their sound signature anyway and I've since sold the replacement pair Westone sent me.
My theory is that BAs are very sensitive to moisture (and possible temperature) in their sound tubes once this happens they do not dry out, IEMs that have a filter in the sounds tube such as the Ety HF5 seem to be able to withstand the stress.
I listen to Indie rock, alt country and the like when I run, my sound preference is for top end clarity above all else, IEMS I currently own that can handle the pace (and moisure) are the RE0, PFE112, Sound Magic PL30, but top of the tree for me is the Etymotic HF5, recently acquired cheaply at Tel Aviv airport, they are lightweight, have extended treble and detail and don't seem to object to moisture.
Anyways, hope I've helped someone, somewhere, but just to recap, best sounding (in my opinion) DBA-02 but very easily damaged by moisture, best overall IEM for running is therefore ety HF5.
Cheers,
Dave