Nitrate is not nitro/methonol fuel resistant. Butyrate is resistant to at least 40% nitro (and can handle 65% for short durration.)

Nitrate shrinks more than butyrate.

You can apply butyrate over nitrate. You can NOT apply nitrate over butyrate.

Nitrate is usually a little less expensive.

When using both on ne plane, initial covering applicaton is done with the Nitrate, and the first 2 to 4 coats of dope will be nitrate. (Nitrate fills and seals quicker than butyrate) The color coats and final clear coat (if used) are butyrate. (if doing a gasoline, electric or unpowered plane... you can do all nitrate.)