Negative effect?

Anywhere from "none whatsoever" to "holy sh!t I thought the 91 cowboys had retired or killed themselves".

I've got 2 years at a regional and feel it made me a much better pilot and recognize the benefits a 121 guy can bring to a 91/135 operation. I also see the liabilities they can bring to, however those liabilities are totally dependent upon each pilot's personality and ability to be flexible.

A good manager & quality hiring practices can separate the proverbial wheat from the chaff fairly well...