Hi decio
I have a GoProHero HD (V1) it's really great for convenience, really small and it has been really handy for action sports. I have the car mount (with sucker attachment) as well as the head mount and the various range of sticky-back clips allowing you to mount it virtually everywhere. Its really great.
TBH as far as total quality is concerned it cannot (IMHO) compete against the likes of a proper digital handy cam like a Sony for example, but its not meant to, its designed to be tiny and convenient. The picture quality is really good (if you keep the housing dust free)
Housings: these are brilliant and come in various styles; waterproof and half open. Make sure you keep the seal around the water proof one very clean and flexible (long hot days dry this out) I use a tiny bit of olive oil which seems to be ideal and keeps it just right. I would advise you get yourself a high quality lens cleaning kit as well as a spare lens kit as just a slight clash and the scratches will ruin your image and this is real bad if you are out in the middle of nowhere just about to film and you scratch or damage the lens inadvertently.
These units are not particularly tough like most people think though, drop it from a few feet or bang into something (yes- in the housing) and it can be ruined (I am on my second one)
Audio comments: this is where it is let down really, as in the waterproof housing- its hard to get much audio unless you are static and even then its hit and miss. Although with the open backed case is much better BUT
Audio advice: the microphone is really sensitive and lets say you have the cam in open backed case and clamped to the windscreen of a Zed with the roof down! When you check the video all you get is wind noise and its a shame. I ended up getting some audio foam (like you see on the end of a mic) and cutting a small piece off to jam in the gap between the case and the microphone hole on the cam; this worked a treat, it's not perfect but good enough. something like you see here
http://www.audiospares.com/product.php?productid=1512
finally would recommend you get two other things when you have the chance
1) a car charger adaptor and a spare battery
2) the screen that mounts on the back of the cam (LCD BacPac) This is a must have when you are new to mounting the cam on something like a helmet or windscreen, because without this its impossible to know if you are shooting the right viewpoint (instead of the sky for example like I did.
enjoy & good luck
IWL
havent yet used it in the car 
