I had the first generation of Lx100 and used it almost only for video. I loved the fact you could easily access aperture and shutter speed. The rotating knob, focus wheel are nice to use as there's no need to navigate to some menu to access some basic functions. For UW video, a poor choice of housing makes a big difference with this camera because you may be unable to properly access those settings. The Nauticam housing provided a full control underwater while it was not the case for Ikelite and Meikon/Seafrog. I initially had an Ikelite housing and that what a bad choice as I didn't have any control to manual focus and then happily switched to Nauticam.
What I disliked the most with the LX100 was some dust appeared on the sensor after some time. This is a plague for this earlier model requiring servicing at some stage. I don't know about Lx100ii but it's worth checking if this issue still exists. Other than that, I loved this camera and sometimes miss it (I moved to GH5s which is way bulkier underwater).