Great concerns, as no one else has yet responded I will give my opinions- other persons might feel differently and I do encourage their comments following this post
You noted not having glass bits. I used to be one of those "glass-pathway-only" snobs; little did I understand how little this actually affected my tastes while vaping (again, your mileage my vary). The Plenty threw all my preconceived notions out the window. Thankfully too, cause I went on to find other non-glass vapes like the Lotus.
The plastic bits, with metal screens and bowls- I was immediately skeptical. But I hung on my experiences with the Volcano and went with instinct... Flavor country is just a cart away.
First, one must understand this vape was designed and fabricated to withstand the abuse of the most demanding and hapless herb enthusiast. It was designed for the coffee houses, meant to be able to handle drops and other horrific abuses. No glass for breaking, but huge rips and flavor to be had.
Next, it IS efficient, in spite of being able to use a lot of material at once. Sure, if you do not use the pads, it does work best with a heavy packed, finely ground cart. However, the Plenty provides a super long session that can go one for over 10-15 minutes of hard hitting that will absolutely get you blitzed.
In regards to your comments about controlling temps, I describe it to friends as a dance that you cannot fuck up! There is no over-burn, or combustion, under any circumstances. You control how hot it gets, but a simple inhale through the whip can easily cool the temps if you find it too hot/irritating. An easy pull of the handle reengages the heater and heats it up when temps getting too low.
I will tell you, I also cough when hitting the Plenty... It just rips so hard, and sometimes hot, that it does often give me the sensation of actually smoking- all without any combustion. Also, having a non-transparent vapor path, I feel many users (and this is merely a hypothetical observation) have no fucking idea how much vapor they are taking in and pull out lung busters till they are in a coughing fit!