My AK70's battery isn't so good now as it is a good few years old and I use it everyday in my car plugged in though the AUX connection, so I am thinking of changing.
Newer models have bluetooth which the AK70 doesn't have and this would make it more versatile - The question is - Does the Sony NW A306, when listening to it in it's best settings and using the wired connection to decent headphones the same, better or worse than my AK70 as the price price difference to the Astell & Kern A&norma SR35 is significant?