It would be a lot better if you could link to the posts that contain that information instead of just listing the affected users.
"My 300 Down /12 Up line with SQM enable (cake and piece of cake) get 180 Down /8 Up."
@jeff is testing with NAT and firewall (but without PPPoE and SQM), I see no issue reconciling these data points. About @DreamAddict I am unsure since his issue is not described verbosely enough, but he gets ~349 Mbps LAN to USB-dongle on laptop (many USB dongles are crap and USB2 top out at a gross rate of 480 Mbps anyway), 63.2 Mbps on 2.4GHz radio and 2,5 Mbps on 5GHz radio, since we do not know about his RF environment and number of overlapping users of the different frequency bands (let alone the capability of his laptop) this sounds about what you can expect in real life.
I am sorry, I feel your pain and lack of satisfaction with OpenWrt on your router, but insulting other users here that are actively trying to help seems counter-productive to improve your situation, no?