Please do. That would be greatly appreciated. I'm considering the ER4 series, PFE 232, Shure SE535, Westone R4, as well as the Heir 4.Ai, all of which I hear are great IEM's for their respective prices. Sound quality, neutrality, isolation, build, and comfort are the biggest factors. The 4.Ai seems to be the clear winner just based on reviews here, but I am worried that the reviews on Head-Fi are too one-sided and has too small of a sampling size, so I was trying to find that review from earlier which offerred good insight.
Yes, I have, but I'm fairly certain it was on an appreciation thread.
It'll be a little while before I get them :p I will only be able to compare to PFE232 and Westone W4R from your list. I'll be comparing other IEMs as well (UE900 that everyone wants; I'm as interested in this comparison as well :) maybe Aurisonics ASG-1.2 and 3.Ai for sure). I felt the same way about the one-sided thing. On head-fi, it either means a lot of hype, or they are really that good.