IEMs are seductive little things - I truly don't understand why, LOL! For some reason I've never felt the same about headphones, maybe because due to the tropical climate I use them much less, but when I got my Sony MDR 1A I reached my end point for overears. They are just very good, very musical and extremely comfortable headphones, leaving me not wishing for anything more.
IEMs I use much more, both at home and in the gym or when traveling which I do quite a bit. I have found what for me are the almost perfect set - the Sony XBA N3, which I recommend to anyone who likes natural sound with powerful bass and clear and potent treble - but still love to try new sets. I'm keen to listen to the campfire products to see how they match up with my tastes, especially the hybrid model. I do have to remind myself that I only have 2 ears, and more than a few pairs, even for different purposes, is a waste
... But they're seductive, something about the technology just appeals.
In actuality, I should concentrate on finding a nice new DAP, as my much loved, nearly to death, iPod classic is on it's last legs. I've got the excellent Fiio e17k attached to an old android phone as well, but prefer a stand-alone player for most things. Budget constraints apply, but I'm looking with interest at that Opus, along with the new Cayin, Shanling and Fiio models.
The curse of too much choice, ha, could be worse...