Care to say which one was "rubbish"?
I'm happy with a Transcend DP200. Excellent video quality, night & day. The supplied mount was awkward for my car - the 'stalk' is at such an angle to make fitting behind the mirror impossible - however I found a short stubby mount (~£2 from ebay) and cannibalised the stalk from that for a permanent fit behind the mirror. It has wifi but never managed to get that to work reliably. The later model is the DP220 with Lithium battery vs. the DP200's super-cap, which seems to me a retrograde step. It comes with a Transcend 16GB card which I replaced with a Kingston 32GB (~£15 from Amazon) for just over 5hr running time in HD mode. I run the power cable into to the fuse box with 'piggy-back' tap fuse (Amazon). Also fitted a timer (~£5 from ebay) so it stays recording after key-off for a predetermined time.