Carbs...Tillitson vs Zenith vs Marvel???

[ETAModel]

I've read where the Zenith carb was used in all original Model A's, but also seen Tillitson and the Marvel carb used and spoken of.

Were Zenith carbs used Exclusively as original parts, were other brands used as original equipment? Is the Marvel part of the Tillitson line?

Lastly, what was/is the difference between the different brands? Pros/cons ? Which do you prefer, and why do you prefer it over another ?

Thanks.

ET