As a non English writer and speaker, I found no barrier in learning.
However, the tutor I found was professional, timely and overall great.
Now, I know that at least one problem, that with my exercises containing numerous calculations, is solved.
Com is one of the finest find and best writing help providers in the USA.
I also like Professor Barrys reading list that helps student to appreciate good writings from various writers.
In the future, i believe the course could be split in two parts, so students can focus more and exercise each part (scicom + scientific writing for papers).
You get what you put into this.