I use an Olympus OM-D E-M5 for street stuff and it is pretty good, but there is one thing that really, really annoys me about it.
E-M5 is slow, much slower than a DSLR, to wake-up from sleep or when
you turn it on. In my street photography I sometimes miss shots because
the camera is waking up very leisurely. When possible I do my best to
anticipate when I might want to take a shot and start the wake-up
process, but sometimes things happen very quickly and by the time the
camera is finally ready the moment has passed. In most ways the E-M5 is
fast and very responsive, like a DSLR, but in this area it is like a
digicam. Even if a DSLR was as slow as the E-M5 it would still have an
advantage because while you are waiting for the camera to be ready to
shoot you could still look through the OVF, do quick framing, adjust
zoom, and then shoot as soon as the camera is ready. With the E-M5 you
can't even do the quick framing and adjust zoom while you are waiting
and waiting and waiting for the camera to wake-up.
Since the E-M5
does not have an OVF it uses battery power pretty fast. If you set it
to never sleep then the camera is ready all the time, but the battery
will run down fast. Also, the sensor and EVF will be on all the time
even during the long periods when you are walking around watching for a
potential shot. The sensor will be heating up and getting noisier.
just got back from a month in Nepal and there were a few times when I
almost threw my E-M5 against a brick wall when I missed a sudden photo
opportunity while the camera took its sweet time waking up.