The HC-V9000 only records in 1080p up to 50fps in either MP4 or AVCHD whereas the HC-VX3 can record at 25fps in 4K and 50fps in 1080p and can shoot in lower light with aF1.8 maximum aperture
Tutorial: Keeping Shutter Speed and Frame Rate In Harmony
The frame rate and shutter speed your camera is set at to create videos is very important and getting it just right can make a huge difference in the quality of your footage.
Review: Panasonic HC-X1500 camcorder. My thoughts.
Sure, it doesn’t have XLR ports and the smaller sensor does have some low light issues, but the HC-X1500 is nonetheless a very impressive package, and as mentioned, at the current knock down price available is simply brilliant in my opinion.