Over the holidays I hired a DJI Osmo to play around with, so here's a few quick thoughts on it. Essentially it was a lot of fun to use, I loved being able to get extremely low or high angle shots with absolute ease. The gimbal itself works amazingly well, responding to movement quickly and accurately. I only had to calibrate it a couple of times which you can do at the press of a button, and calibration only takes around 30 seconds.
The downside is the camera, the Osmo comes with the Zenmuse X3 camera which has a 1/2.3 sensor. After trying the various resolutions and frame rates I can say that 4K (UHD 3840x2160) is the best. I tried shooting 120fps in HD but the quality is terrible, basically unusable, 50fps is ok but still not great. Due to the size of the sensor it's not that good in low light, so I'd recommend only using it in very well lit situations, mainly outside on sunny days. However the dynamic range is not great and quite often I found the sky to be completely overexposed. I will admit I had everything on auto and didn't delve into the manual settings at all so that might help. You can use the newer Zenmuse X5 cameras with the Osmo handle, they give you a 4/3 sensor for better dynamic range and a M43 mount so you can use different lenses, but with a hefty price bump.
I don't think the Osmo will find it's way onto any film sets any time soon, it's not a patch on a decent camera with a steadicam or big gimbal, but obviously it's not meant to compete with them. It's definitely useful if you're a self-shooter working within corporate, or a no/low budget filmmaker looking to get the odd cool shot here and there.
Below is a variety of footage I shot over Christmas whilst on dog walks with my family. As such most of the footage is 'following shots', which personally I love but some might find boring. Either way it should give you an idea of what the Osmo can do during impromptu situations. Put simply it's a lot of fun to use.
(Yes I added a 2.35:1 crop to try and make it more cinematic, that silly old trick).