Ninja
Foodi Dual Zone Series
Dual zones excel, but bulky with small baskets.

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I really like my ninja flexdrawer I got a few months ago (I got the smaller version - 6.6Litre because the big one was HUGE and I didn't have the bench space for that monstrosity!). It's been great for us (family of three) and I like the versatility of being able to just use half the drawer for eg a handful of chicken nuggets for my kid or both sides for eg a big slab of pork belly. What I love the most though is the easy clean up - the entire drawer can just go in the dishwasher and you're done. We previously had an oven style (instapot brand I think). That maybe had a bit more versatility for our circumstances at the time (temporary kitchen with no actual oven) but cleaning it well was impossible so that alone would put me off recommending it. Edited to add the 6.6l flexdrawer would probably be big enough to cook a mostly complete meal for 2 people - eg a 2 person roast dinner in the full drawer or a protein in one side and a veg in the other side (maybe add some rice or something cooked with another method). Depends really on how you cook and eat - for dinners I tend to mostly use it for sides (eg roast potatoes and roasted broccoli etc) and cook my protein on the stove top or cook the protein in the full drawer and serve a salad on the side. I like the flexibility that you can have different cooking times and methods for each side so you can cook salmon fillets and roast potatoes all set at once but they each come out perfectly cooked.
I love my ceramic coated double sided Ninja. It’s a piece of cake to clean and crisps perfectly. I’ve also had the Ninja that was smaller and the Instapot brand. and I guess they were Teflon. It didn’t take long before both of them were a pain to clean. I’ve never seen the glass ones. I suppose they’d be not to hard to clean. Are they tempered glass?
I can recommend the Ninja Flexdrawer ones. You can use it as two separate drawers or one big drawer. I rarely use it as one big drawer but it’s very handy to have the option.
I use the Ninja Airfryer Foodi FlexDrawer. It's a European model, I've had it for a year and a half and it's great. I don't really use the separate zones thing, though. But you can easily airfry a whole small chicken in there.
Still working fantastically. Cooking consistency has been solid and the noise is medium-low. It's not bad, but it'll make you turn the tv up a level so that you can still hear it well, if you know what I mean.
The ninja flexdrawer one is awesome. Can I ask why being diagnosed as gluten intolerant means you need to change airfryer?
I would recommend either the Dual Zone or the FlexDrawer. We've tested very similar Ninja models and they've both performed very well and are easy to clean. I would not recommend the DoubleStack. As you mentioned, the rear placement of the fans and heating elements does lead to very uneven cooking (food closest to the back gets cooked much faster). A rating of 1670 W is very typical for North American air fryers. You mentioned that your previous model was rated for 2300 W, which means you're probably outside of North America. Most dual-basket models in the UK, Australia and Europe will draw 2300+ watts, and the added power is absolutely a benefit for cooking speed (especially for dual basket models where two chambers are cooking at once). Lastly, in my experience the plastic smell does go away after a few uses. This is common for most brands of air fryers!
I would recommend either the Dual Zone or the FlexDrawer. We've tested very similar Ninja models and they've both performed very well and are easy to clean. I would not recommend the DoubleStack. As you mentioned, the rear placement of the fans and heating elements does lead to very uneven cooking (food closest to the back gets cooked much faster). A rating of 1670 W is very typical for North American air fryers. You mentioned that your previous model was rated for 2300 W, which means you're probably outside of North America. Most dual-basket models in the UK, Australia and Europe will draw 2300+ watts, and the added power is absolutely a benefit for cooking speed (especially for dual basket models where two chambers are cooking at once). Lastly, in my experience the plastic smell does go away after a few uses. This is common for most brands of air fryers!
Ninja
Foodi Dual Zone Series
Dual zones excel, but bulky with small baskets.

COSORI
Turbo Blaze 9-in-1 6QT
Effortless to clean and quiet, but no viewing window.

Ninja
Foodi Air Fry Oven Series
Unique flip design, but shallow and air frying debated.

Typhur
Dome
Self-cleaning and quiet, but expensive with shallow interior.

Breville
Smart Oven Air Fryer Series
Great oven replacement with large capacity, but poor air frying.

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Ninja - Crispi Pro 6-in-1 Countertop Glass Air Fryer

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Breville - Smart Oven Air Fryer Series

Ranked #1
COSORI - Turbo Blaze 9-in-1 6QT

Ranked #1
Ninja - Crispi Pro 6-in-1 Countertop Glass Air Fryer

Ranked #1
Ninja - Foodi Air Fry Oven Series