Airmail – A Real Sparrow Alternative?

I've been trying this out side by side with sparrow for the day, and I like it's looks, though it seems to be a little choppy (I do have a rather sizable gmail inbox), here's hoping the developers keep up the good work!

I wish it had the ability to collapse width down to one column like sparrow does (cmd + shift <- || -> ). That's probably my favorite thing about sparrow.