Not had a dash cam before however coming around to the idea. Been looking into this a bit and the BMW Advanced Eye v1 is pretty old now and the picture quality not quite up to scratch compared to some of the newer models.
There's almost no information on the Advanced Eye v2 on the Internet but I did find one snippet that seems to suggest it isn't available until May 2018. However from the 2 pictures of it, looks to be much nicer than the v1.
While third party ones have lots of good options they don't seem quite as clean if that's the right way to put it. For instance the car can pick up the battery drain and alert you or the comfort access will stop working because the battery drains too low, etc. Then you need additional items to get around that, maybe another battery, etc, etc.
Hence if I do get one I'd likely pay a bit more just to have a BMW one as it will be guaranteed to cause no problems with the car. Or well if there are problems I'll have what my customers can sometimes say as "One throat to choke". Has to be a problem BMW solve
Anyway will see what reviews of the BMW v2 come up as and cost as I've not even seen that yet.