Muncie M20 vs. M21 vs. M22

[cammer427]

There are a few companies producing new Muncies with different gear options than were available back in the day from the factories. My question concerns the Muncie transmissions that were equipped in cars back in the '60s/'70s (factory gearing, etc.).

What were the benefits and disadvantages of the factory-spec M20, M21 and M22 transmissions? Which were better for what circumstances, types of driving (racing, weekend-only cruising, daily driving, etc.)?

Obviously the M22 was the most durable of the three. I've heard the M20 was best for off-the-line acceleration due to it's wide first gear (are wide-ratio transmissions truly better for off the line acceleration?).