ok, as someone who had both i can tell you :
1) the TF10 is heavier
2) the IE8 cable CRUSHES the TF10 cable, its smooth, light, easy to untangle, while the TF10 cable is stiffer, has memory effect, which means that as it ages it stiffens with marks of the tangling, i have had issues with cable weight and shape distorsion which seriously affected fit and seating, i would consider the TF10 cable as a serious drawback,
3) from what i can recall, the TF10 is faster and has slightly better trable, the mids are more or less the same, and the IE8 beats the TF10 in base any day of the week, soundstage goes to the IE-8, by a mile (literaly),
4) i found the ear hooks that come with the IE8 usless, but i never had issues with the fit,
5) isolation with the TF10 is superior to the IE8, many suspect that the IE8 is an open IEM due to the force of the music and the soundstage, but once music is playing, its much less noticable,
6) the tips which come with the IE8 are a bit poor, the foamies look like the olives at first, but they are somewhat stiffer, which is good on the side that they absorb less sound, therefore they affect the range less then complys and olives, but this extra stiffness makes them less molding, meaning they isolate less and are less comfy to wear, i use either sony hybrid or UE silicon with my IE8, im still waiting for a chance to try the new monster hybrid tips (half silicon half foam) but i havent found a place that sells them on their own outside the US,
personaly, i like the IE8 better, the bad fit, the lack of comfort, and the fact that i had to wear them upside down to get a decent seating out of them is a clear indication you should really like the sound to accept the triple.fi in your life, and for me, the IE8 just sounded better, the faults on the IE8 (mainly the isolation) are much easier to accept then the piss poor ergonomics on the Triple.fi, and im a little bit upset with myself that i accepted those flaws for around 6 months before giving up and getting better earphones, not to mention the cash pissed away on those disposable 1 use comply tips,