I own both the Z2 and 1020, the Z2 does not have OIS but the videos are really well stabilized by software and the 4k resolution is a gimmick wich only records for 3 to 4 minutes. If i really have to choose for quality with no gimmicks i would recomend the 1020. The Z2 is good by smartphone standards (up in the high end) but the 1020 is still in a league of its own, not only video but also the recorded audio is way better than the Z2. The Z2 is really an allrounder wich does not really excels but does everything well (apps, ecosystem, dual speakers, good cam etc).