FitEar has a very special house sound. Some will like it, others not. But one thing is clear for me : they are very expensive for what they deliver in terms of SQ. It is justified by the build quality and comfort though. They are the only CIEMs with such shallow fit and still good isolation.
In terms of sound, I had the Togo 334 on loan for a while...the bass is very bloomy, not to say bloated. The ultra slow decay didn't do it for me.
I prefer the 335DW, that I owned for a while. I had ear problems at that time so I had to let them go, but they have great full mids, very nice powerful ass and smooth highs. Not for people who like bright or sparkly or analytical or neutral. I tried the SR briefly, seemed more towards neutral (but not there at all still). The Monet 17 sounded a bit weird to me.
These are special IEMs, but ones that should really be tried before buying.
If I had to go Japanese Unicorn, I would no more tempted by the Sony customs.