I thought I missed the first outgoing batch, but I got my Massdrop shipment notification when it was already delivered to my doorstep.
First impression after using it for a couple hours is that it's a decent, solid mouse. I like the shape and feel -- the glossy white is very slick but no issues with that. The rubber cable is soft and flexible, quite nice. The LMB and RMB on mine feel identical to one another and don't seem to have any build quality issue unlike some other mentions here. However the clicks are a good bit louder/clunkier than those of my G400s which uses Omron D2FC-F-7N switches, I much prefer those. The mousewheel is softer with less "crispy" detents compared to the G400s, scrolling is quieter. No real problems with drag except if I'm pulling straight down with some palm pressure on the back; I'm a fingertip gripper and doubt I'll ever have to deal with that. Might be problematic for palm grippers that really rest their hand on the mouse. The sensor is great and I like the low lift-off distance.
Only things I would really like to change would be to have some softer/quieter switches for LMB/RMB and some way of disabling the lights. It's green at 800dpi and not all that garish but I could do without it all the same. I got this mouse as a stopgap because my Logitech G400s is dying (random disconnect/reconnects now & then) and the current Logitech releases look ridiculous. Once they come out with a normal looking mouse with the 3360/3366 sensor I'll be going back but I'm quite happy with this purchase in the meantime.