While I haven't heard the other IEMs listed here, i've had the MC5 for aa bit over a year. They look nearly new. On this score, I always carry mine in a wallet-sized case so they stay nice.
They have a very pure sound and are lovely in revealing the subtle breathwork in cantata singing and give a very precise rendering of pitch. i don't think they give the most dramatic sound for the big symphonic works, so that's worth noting. For myself, I find this is balanced in part by their clarity and ability to give view into the orchestral parts and solo lines.
If the quartz-locked precision with pitch sounds appealing, then worth looking into these. If foundational support of bass is key, then maybe not. For my listening, if I buy more expensive IEMs in the future, etymotic willl definitely be on the list.