Glock Talk is keeping from getting to bed, so I'll keep it short.
Are we talking body worn camera or car camera here?
A good, digital car camera system is going to gost $3k-$5k fairly typically. There are cheaper systems and spendier systems. I have experience with Watchguard and L3/Mobile Vision digital systems.
Watchguard was "adequate", but we had issues with intermittent corrupted recordings that had to be recovered with special software. The small department I worked for at the time could not afford the infrastructure a digital system that stored video to a hard drive would take, so the DVD based system was a good way to get in to a digital camera without all of the back end work. They changed the body mic design three times between the first one we bought and the second one. I think that was just over a year. It took a lot of beggining to get them to comp us a matching body mic when the junk one the first system came with **** the bed. Overall they were easy enough to work with and I liked the menu system and so forth on the camera.
Current department is L3/Mobile Vision (as are at least two other agencies in the county). We just recently replaced our camera systems with the newest version, which is higher resolution. The quality is very good, the security, storage, and web based access are good. The body mics are good. Our biggest issue is that the larger resolution has led to greater recording file sizes, which coupled with wifi oversaturation and congestion, are killing are wireless uploads and forcing our supervisors to manually swap out a bunch of cards every shift. The back end infrastructure is significant. I believe that our "live" video server has 14TB of storage and they have a DVD writer spitting out several DVDs a day to archive footage. There are drawers full of DVDs and they have every piece of video ever recorded on the system, which goes back to maybe 2004 or 2005.
There are plenty of limitations to car camera systems. Fixed point of view being the most significant. The camera only sees what is in front of it. Narrow viewing angles contribute, but are necessary to keep things from distorting. Body mic performance is not always great. Perspective is difficult ("are you sure they missed heel to toe by more than a half inch there, officer?"). There are plenty of good things and plenty of negatives, too. More good than bad.
If you're considering body worn cameras, a truly "good" system is going to run $900-$1,000 per unit. When I refer to a good system, I am talking about build quality, durability, infrastructure, etc. The only two decent body worn systems that come right to mind are VieVU and AXON Flex. Both have back-end software packages to automate uploads, which many of the cheaper cameras don't. I am nearing the end of a trial of AXON Flex and am extremely pleased with the low light video capability. Better than any other video camera I have seen. I have made several drunk driving arrests while wearing it and the video is very good.
The downsides to body worn systems are also very numerous and the limitations of the systems are not always readily visible. For example, the field of view is still relatively limited, so things you see with your peripheral vision simply do not appear on the camera. I have a thread floating around on my experience with AXON Flex somewhere, as well.
"Logic is rarely the engine that propels a police department forward."
-David Simon in "Homicide"