Wanted one of these for ages. Had the 43mm Zenith Chronometro Tipo CP2 in both steel and bronze. Steel one is just right I think but the bronze cased version wears too small - for me at least I found it disappeared on the wrist - though the steel one was long gone by the time I arrived at that conclusion.

Also had the 48mm Zenith Type 20 Pilot GMT model which was something quite special and striking - sold to raise funds (sadly), but it wore large, as it was designed to do, a little impractical for every day. I always wondered if the bronze cased 45mm model would be in the Goldilocks zone - just right for casual, daily use. And I think it is. This one dropped into my lap unexpectedly and I'm having to reshuffle the collection a bit, but worth the effort. I was chasing the chronograph at one point, but switched to the 'Extra Special' - the simple three hand design is just so 'right'.