Well, both sides are guilty.
There are those who are claiming M1 is not amazing because it's not able to beat multi-core performance of some high-end notebook and desktop chips, or that the GPU is not able to beat dedicated GPUs from last year, etc...
And then there's the other end of the spectrum where people are claiming the fanless MacBook Air can run circles around Core i9, and that the upcoming chips for the 16" MacBook will completely dominate the competition, etc...
I'd really like to quote something from Apple's keynote: the 13" MacBook Pro is the ultimate expression of the M1 chip.
So... say, we get an M1X for the 16" MacBook Pro and a M1Z for the iMac, Mac Pro... those will probably be more optimized for performance. Meaning... they probably won't be able to achieve the amazing battery life, nor the nice and quiet performance of the 13" Pro and Air that were announced. Those chips may beat whatever AMD or Intel can push out, but I'm under no illusion to think they won't have any drawback. Likely power consumption will shoot right up, and we'll be back to the same 10-hour max battery life, with maybe 4-5 as the worst-case.
Really, it's a balancing act, and I think Apple has already hinted at the fact that the 13" MacBook Pro that was just introduced is the best performance/watt ratio already. The rest of the scale may not be linear, and we may see the fastest chips equalize out. So iMac and Mac Pro may not be significantly faster than Intel or AMD offerings. The 16" Pro will probably not have amazing battery life. Such is the "realistic expectation" I'm talking about.