a laptop bag stuffed with books and papers will not fit
It's all about planning, and understanding what will fit.
I have an overnight bag, into which I can fit laptop, notebook and enough clothes/personal hygiene items for an overnight stop, which complies with Flybe's measurements and fits (just) into the overhead bins on the Q400.
I actually find the Q400 perfectly fine for the trips I have been on in it. You always have a window or an aisle, the view out is good (due to high wings) and legroom is better than some charters I have been on.
As for noise and vibration, after many years sat in the back of C130's, the Dash is like a peaceful haven by comparison.
It does seem to be a bit of a challenge to land smoothly though ;-)