I'm lucky enough to have been able to borrow each of these for use. I borrowed the VIRB from a friend a few months ago to do some course video for a local race. I only had it for a few days. I happen to have a pair of GoPros at home right now that I've borrowed from another friend to do some more course video for a local race. I am also evaluating their use for motion capture in my fitting studio, as the GoPros have some nice high frame rate options (120 fps at 720p). I'll try to leave that aspect out of my comparison though, as I am not sure my needs for the fitting studio are exactly normal.
For course video, catching action video, etc., it's hard to really say one is much better than the other. They both have their strengths and weaknesses. I am certainly not the most keen-eyed, but I think they both do really great video. Most of what I've done has been in good sunlight, which obviously helps good video, but neither has left me disappointed. The VIRB is nice when you can sync the Garmin data - kind of a neat feature. The VIRB does seem to be a bit more hefty, although I feel the shape of it is less clumsy, for lack of a better way to put it. Of course, that also depends on what kind of video - the more upright shape of the GoPro would go better with a chest strap, but I like the VIRB for mounting on the bike or a helmet. Maybe it's because it looks more aero? lol!
I find the GoPro mounts to be kind of odd, with the interlocking tabs and thumbscrew thingy. My fine motor skills suck, and I look like a monkey fucking a football trying to change them. I do like some of the additional features GoPro offers, like the BacPac things such as the extra battery pack or the LCD.
I actually like the record button on the VIRB better. It's more tactile and makes it obvious the camera is on. The other thing I like about the VIRB is the built-in LCD. I like knowing what I'm aiming at.
I hope that helps a little. My time with each has been fairly limited, so I can't say I've really gotten as deep with either one as I could (for example, never used the VIRBs WiFi, and haven't had much luck with it on the GoPro yet). This is definitely not a DC Rainmaker-quality review, that's for sure!
Travis Rassat
Vector Cycle Works Noblesville, IN
BikeFit Instructor | FMS | F.I.S.T. | IBFI
Toughman Triathlon Series Ambassador