this was one of those moments that I had to make a very quick decision and I have not done enough research on Q series. K-01 will take all my lenses that I have for K5. And what I have read about the image quality on Q last time did not leave a very strongly memorable impression with me. Either way, the prices are much lower than what used to be new. For the pure joy of owning something totally different from K5, I chose the Q.