I'm definitely a ripper, but I get quite a few nice clouds off less herb in the Air. I guess it doesn't REALLY matter as long as those 3 rips are getting me as medicated as 10 thru the Air.
I have both the Air and the Hopper.
The Air definitely lasts through bowls for the whole 10 minute session, but it also vapes uneven (more brown on the top rather than throughout the whole thing... I have the screen in too. anyway!) So the Air is definitely nice. However, the Grasshopper, IMO doesn't really compare fairly. The Air, while convection, seems to have difficulty keeping the heater stabilized, which in turn affects vapor production. Personally have never found using it through waterpipes very good; never enough vapor buildup, etc. However, I really like the ability to just go back to it over a period of 10 minutes and get a good cloud each time.
The Grasshopper is kind of the opposite of a lot of this. Still convection, but using an on demand heater with no problems of temperature stabilization. Technically, the Grasshopper is not a session vape whatsoever, however I still get some good mileage off it with 2 or 3 friends through a waterpipe. I prefer to use the Grasshopper through a waterpipe as well. In public, obviously I'm not going to carry some glass around with me, so it's the only time I really choose to use the Grasshopper without a waterpipe.
In terms of "sipper or ripper" the Grasshopper is still definitely a ripper. I find sipping often leads to the auto-shut off (doesn't detect the draw). I'm ambivalent on this. It's nice to sip the Air, sometimes I can rip it and not have the temperature drop. The Grasshopper, I have to rip it, but it always delivers.
I prefer the Air for vapor without a waterpipe, but every time I would still choose the Grasshopper over the Air (and Flowermate lol). The thing is, with the Grasshopper I can put in a little bit, turn it up to 2.2 and milk my D020 white, and clear it and milk it 3 or 4 times on a single hit. Turn of the button, get 1 or 2 more milked hits. If I'm not high enough, I will turn it up to 3.2 or 3.3 and do the same. The Grasshopper really is a cloud machine, but I think waterpipes really show it off.
The vapor to the Grasshopper is pretty hot, which is why I prefer to use it through waterpipes. But, having also used both the Air and Grasshopper in public, the Grasshopper is still more discreet, easier to manage, and fun as fuck. I mean come on, who doesn't like the idea of taking a nice 15 second hit, holding while you walk past a nice couple, and then cheese and exhale a giant white cloud that makes you feel like you just hit a boxmod.
With all of this said, I still can't decide on a favorite. My order is definitely GH, Air, FM, but I still love to use all of them. Tastewise, the Grasshopper and the Air... maybe the Air has slightly better for the first few, but the Grasshopper keeps it more even throughout. After 5 minutes of a session with the Air, I need to stir it, which really bugs me since the glass is hot, to maintain good quality tasting vapor.
I do still stir the Grasshopper. I think I overpack it, as I have a really bad scale that can't scale anything less than 2 grams. Ridiculous, but it is what it is. So, usually after 3 or 4 hits on 3 or 4 (lol) I will open up the mouthpiece and push the bits on the top down and stir it a bit. I think the Airpath for the Grasshopper can begin to vape uneven if over or significantly under filled.
Sorry for the tangent, I just kept writing things.