I can handhold the M8 at 1/15s quite reliably, 1/24s is never a problem. The - by Leica standards - somewhat raucous re-cocking of course happens after the shot. I'd say this is a very nice camera to hold steady. I leave it on A most of the time because in most cases, I can estimate the metering results quite well, but presetting the shutter speed and then adjusting the aperture also works well for me; I'm less comfortable doing it the other way round (presetting the aperture, adjusting shutter speeds manually), though that's probably just me. A mode gives me sufficient control for my needs.
Whatever you do, take care not to blow out the highlights - there's extremely little leeway even in the DNGs to correct for that; shadow recovery is better (though not great). You may have to learn to compromise - but the images from the camera are well worth that. As for ISO, try to stay at or below ISO 640 - everything above is definitely not up to any current standards, though you may get away with b&w conversions; that's because while colour noise from this sensor is really rather ugly, it looks pretty random, translating to something akin to grain in b&w ... which can actually look quite pleasing.
M.