If you have $, A6300 seems to be worth it (other than potential 4K overheating issues)
A6300 isn't that much smaller than dSLR, but it's cheaper and seems to have more bleeding-edge technology (autofocus, 4K, burst)
if you want a true "companion" camera to a dSLR, look at the RX100 line. Point & shoot, 1" sensor
no interchangeble-lens, but it's small and can bring to concerts
a6000/a6300 is more of a replacement camera toa dslr
