Hey,
You can check out the video review I did on the M201. I love it, but I prefer harder draws. Let me fire one up vs the M401, sec..I'd say slightly lighter than my EVO is, with a new atty on each. Not J118/VX2 light, I'd call it a 'medium' draw, with the M401 being similar, J118/VX2 lighter, and 510 harder draw. The J118/VX2 is like an empty straw for me, the M401 and M201 are more like 'straw with something in it but not milkshake.'
I really like all 3 - 510, M201 and 401/EVOs, just depends on the need/urge at the time.
@Chris - I hear there are some longer carts out for the M series..do you have any or will be getting some?