Copy and paste from your Argos thread;
“Based in my SJ4000 (not 4000+) I’d go with the GoPro at that price. I’d say the video quality is as near as makes no difference the same, but the build quality, on my SJ4000 at least, is pretty poor. For example, getting the buttons to recognise being pressed requires 10,000 tonnes of force which makes it very irritating to use.”
I’m sure my SJ4000 was around £35-40. Probably fake to be honest but the image quality is great.
Personally I’d go cheap (ie. SJ4000 not the plus), see if you actually use it. If you do then consider at that point if it’s worth upgrading to a GoPro. Best thing about the SJ’s is that the mounts are all GoPro compatible so there’s no danger in investing in all the mount kit if you upgrade to GoPro later.
Only other thing I’d add is to definitely avoid the TomTom, Garmin, Contour, Sony ones. Unless you are riding at Red Bull Rampage, any helmet mounted video looks totally mince-core due to flattening of everything. Handle bar mounting is just too rattly. That leave chest mounting as the only viable option and you really need a GoPro shaped camera for that.