I'm sure I've discussed this elsewhere but for the sake of beating down the JH13 hoards they are not for me for the following reason:
situations where I would use IEMs do not lend themselves to critical listening, i.e. I'm using the isolation to block out extremely loud noises. situations where I would use IEMs are somewhat hazardous to their health making expensive IEMs a bad idea. $1100 for something that is exceptionally fit dependent does not sit well with me. I am simply not a fan of $1100 for things that in my opinion have ~25% resale value. In situations where I actually do listen critically I do not want or need isolation.
Now, alll that said, I can certainly see why the represent a very good option for other people. If I commuted on a train, traveled frequently on a plane, or lived in an environment where closed cans where a benefit it would be a pretty easy decision.