1. The MSU report ("performance mentioned by AOM sources") with known methodology has to be verified, but that one demo with hand picked scenes and undocumented codec settings are totally the definitive answer.
2. On the performance side, we don't know the complexity of the codec yet. And on the cost side, HEVC is going to be more expensive by definition, due to being an rent extraction scheme.
3. You can't compare reference WIP codec with optimized one. The premise of the entire paragraph is just wrong.
AOM dev here.
Currently, aomenc takes ~100s to encode a single 4K frame.
Which means to encode live 4K 60 FPS, you need to multiply the encoding speed by 6000 (!).
Indeed, the codec isn't fully optimized yet, and the required performance improvement is huge.
Of course this freaks people out!
On the other hand, reference video encoders are famous for being ridiculously slow. The JM (H.264 ref encoder) had similar encoding times, and this didn't stop H.264 from being encoded live.
MSU measures in SSIM and PSNR. SSIM and PSNR, I think i need to say no more. The one demo was done in IBC with industry expert, but not only that but many other independent test. Needless to say AV1 isn't finished yet so it isn't a fair test anyway.
The latest video show  shows AV1 still isn't finished yet. And lots of update and changes were still put into place at this stage of development. So any 2017 made comparison is moot at this point. But with all these improvement it is finally looking like the 30% bitrate savings ( in subject measures ) that they said they HAD from the start.
We dont know the complexity of the Codec? Oh hell yes we do. AV1 is complex, much more so then HEVC. It isn't more cost effective by definition, because AOM has to figure out how do make it much more speedier.
The last report of AV1 is roughly 200 - 350 times slower then VP9. And VP9 is already quite slow. The Reference Encoder for AVC or HEVC were only in the 50 - 100 times slower range. Also worth mentioning the Reference encoder of both AVC or HEVC wasn't even tuned for quality or speed, this is radically different to AV1 reference encoder. Whether AV1 can be optimized to being only 4x slower then HEVC remains to be seen.
So there is absolutely nothing in this pieces that is even propaganda. But lots of valid scepticism, as an industry and business you have to do the maths and calculation. And AOM must work to ensure these concerns are being solved and expectation.
Lastly, just because you like free, royalty free, and hate HEVC payment, doesn't automatically mean AV1 is best in everything. This kind of fanboyism or whatever -ism is spreading like wild fire in every circle.
The codec is still years away from being widely adopted. Its encoder is still highly unoptimized, to the point of it taking tens of seconds to encode a single frame.
Sure, but that statement is valid for every single codec in development phase. AV1 is not an exception.