Will that stand even to other one-chip embedded architectures
A good 68K can outperform them, hands down - on a clock per clock comparison.
But what do you really want?
If you have an A500 or A600 or A1200 then you ideally look
* for a good CPU card that does not run to hot in your Amiga case. Am I right?
* and you want a card which works well with your Amiga power supply,
so that you do not need to use a 100 Watt PC power supply for it.
This means for many chips your AMIGA does not have good enough cooling and not good enough power supply.
An FPGA based 68K would be happy with this cooling requirements.
And performance wise it can beat PowerUP PPC cards
and does beat hands down stuff like 240 Mhz Coldfire or low clocked ARMs.
So with the low end chips a good 68K has no problem to compete.
Do you want to run 68K code?
Then this means you need to run 68K in emulation on your ARM.
In this case a good 68K can easily compete and beat the absolute high end ARM chips.