I have a gopro hero 3+ black (nice name, eh? What the heck does it all mean?) that I got at Costco on sale, and I have a RideEye that I preordered for a reasonable amount of money before they jacked the prices. Actually, $149 looks pretty reasonable again, go for it.

The go pro picture quality is superior and it's not close. RideEye is pretty good though. It's hard to see license plate detail in strong front or backlight situations, or at night.

Go pro handlebar mounts suck, I got a k-edge combo garmin/go pro mount and it's fantastic.

I also got an extended battery for the go pro, and used it on a century Saturday and didn't run out of juice. It's about the same size as a go-pro in a housing, so not small, but very convenient. Much better than carrying a handful of those small go pro batteries and switching them out.

the RideEye is fairly heavy and vibrates like heck on the included rubber band style mount. If you're just using it to document bad driving, it's probably OK, you won't want to compile ride videos for youtube on that mount. I bought the go-pro mount adaptor and now I need a seat post go pro clamp for the ride eye - the plan is to have go pro in front, ride eye in back.

You can unscrew the rear panel in the ride eye and put whaver size chip in there you want, they're just microSD cards. I bought an 8 GB ride eye, it now has a 64GB card in there. For some reason, I can't get the date and time to set on the rideeye - I follow the directions, update the text file, do all that and then still the wrong date. Blech. The battery life is very long though, so it's a better set-and-forget option than a go pro, and will automatically save a file if it detects a crash (or you can manually do it). Most of these devices break the files every 17 min. or so anyway.

Hope that helps.