I find the HD25s to be pretty detailed. However, it's hard to compare the two because they are very different products. IEMs are always more comfortable for me and IEMs isolate the most. Also, IEMs have that major portability advantage. However, the HD25s are great portable headphones. Trust me on this one, these things are VERY well built and nearly indestructible (headphone wise). That's why I find the HD25s to be more universal than the IE80 in terms of build, portability, and sound. I haven't found a genre I didn't enjoy with the HD25s yet. With that said, I don't own the IE80s myself, BUT I have had a thorough listen with it. They both sound great. Also the vmoda M-80 is a great alternative as well.
I am currently using a Sennheiser PX-100 for my iPod, iPad, and Vita. I really like its combination of comfort, durability, and sound (so much so that I bought a second pair to keep in reserve in the event that the first pair breaks). Would either the IE80 or the HD25 be a worthwhile upgrade?