I have to agree, the MZ-S is a real pleasure to use. Even when I'm not using it, I want to pick it up and take pictures. As well, the data imprinting is very useful. If you shoot several rolls of film in a single day, it's easy to put them in order (over 160 rolls so far, and more pleased with every one).
The AF is really good, even in dim light. As for it being fiddly to change AF sensors, when the Auto setting doesn't suit the job, like for a portrait vertical, I just slide the switch to Lock and use the sensor I used last time (usually the second from the right, to line up with the model's eye). It's rare that I need to lock on another sensor, but it's not that difficult to choose another. The MZ-S may not suit everyone, but it certainly suits me. Pat White