Really liking the performance of the D020-W. Know this one has already fallen off the top of the heap here, but wanted to share my impressions.
The small hole of the mouthpiece makes cleaning a pain in the ass, but works great! The reduced airflow gives better control of your draw - and allows for slow, smooth diffusion. IMO this lets you milk her slow and keep more flavor while still cooling and moisturizing the vapor. Drag is minimal and seems more related to airflow at the mouthpiece than diffusion. Percs are not all exact same width, but close enough that most fire every time. My second one percs well too, but only water tested it. The mouthpiece hole is much smaller than the other, so am anxious to see if it performs as well. Water testing was a bit different, but seems like hitting it will be about the same.
Size is a good compromise of volume and ergonomics. A little more volume would be good, but this baby feels nice in your hand and is easy to handle with a nano perched on top. Like it much better than the D020 because of increased volume and sidecar. Very nice to have the nano off to the side instead of right at the tip of your nose.
It seems to be about 1/2 (maybe a little less) the volume of a jhanpixel UFO showerhead and the mouthpiece is on the other side of the can. Both took me about a session to get used to. If prices were the same, the jhanpixel would be my choice hands down. But, at 20% of the price I think I might opt for the D020-W. Not getting rid of either anytime soon - as similar as they are they both have their benefits and shortcomings.
Very glad I picked these up! Will be replacing my D020 as a travel piece, and will definitely get some use here at home. Just have to get over the fact that it takes a while to clean. IMO, at $30 shipped, this is another giant-killer from DHGate.