1/4000s would be nice, either by electronic or manual shutter (or hybrid like the FM3a). I have a brace of electronic M7s that have had no trouble in two years, but recently was seduced by the idea of a mechanical backup. I bought a used M4-P (1982 vintage), and had to spend $219 getting it overhauled for the slow shutter speeds which were unreliable, among other issues (RF misalignment, poor bottom plate fit, fogged VF). Hopefully, the M4-P will serve the role I envisioned for it now, and it seems happier. It will take a bit of getting used to the M4-P shutter dial though, since the placement is less ergonomic than the M7 one.