I've used the Pax 3 for some time now. I REALLY like the thing. I use the 1/2 pack oven cover as it is just me that uses it, and I find it is better to do a few uses over a couple or 3 days and then when there is little "smoke" or little effects, I merely use the provided tool to scrape out the spend herb and put in some fresh. I love how I can control the temp pretty precisely with the Android Blue Tooth phone app.
I tried the attachment for the concentrate and it works as it should. I used a press to make up some rosin and tried some of that in the PAX 3 . It has a different flavor profile than that which you get when just using dry cannabis herb. A little more difficult to deal with in regards to cleaning up afterwards, but a good soak in some 95 % high proof ethyl alcohol does wonders. Also using EtOH on the pipe cleaners sent along goes a long way to cleaning the tube and also some EtOH on a cotton swab is great for the insdies of the oven, the screen and around the covering.
I must say it is VERY economical in the mileage you get off one gram of cannabis. When you smoke in a pipe, bong, or rolled up, there is a certain amount of cannabis that goes up in smoke before you get a chance to get all the goodies out of it. With the PAX 3 it is only what you are drawing at the moment and the moment you are done simply push the power button and turn it off for the next session. Like I said, I get 2 to 4 sessions, not on the same day, with a loading of a 1/2 pack oven which is only about .17 gram compared to .35g. for the full oven load.
The charger is rather unique in that you use USB on the power end and then there are 2 points that are magnetic that automatically align to the charge points on the outside of the PAX 3 on the one side. Easy to charge, and appears to last quite a while.