I am not entirely sure how fair of a comparison I am making, but I am open to suggestions on how to better compare the hypothetical output of a font designed using METATYPE1, where a Type 1 font would be directly generated, versus a font designed using METAFONT, where a Type 1 font is generated using mftrace.
For my experiment, I chose to compare glyphs from the Type 1 version of Computer Modern maintained by the American Mathematical Society, which was presumable crafted by manually tracing the bitmap version and optimizing various aspects by hand, with glyphs generated by mftrace on 3000DPI bitmaps generated from the METAFONT source. I could imagine that it might be fairer to compare the result of using nearly identical METATYPE1 and METAFONT source to generate the Type 1 glyphs, but then I would be biasing the design process towards the limitations of METATYPE1. I had considered using the METAFONT source for AMS Euler, because the source is simply the outline and would be easy to convert to METATYPE1.
I also decided to use glyphs with plenty of curves for the test, as I figure that tracing software can probably do a pretty good job with straight lines.
In any event, I will leave it to you to decide whether you can distinguish which is version is which below. The order in which the two versions appear differs for each of the three examples below.
As you might have guessed, my opinion is that results are so nearly indistinguishable, that given the design limitations of METATYPE1, it would make much more sense to work with METAFONT and mftrace, and use FontForge or a similar tool to add hinting as a postprocessing step.