Fluval Spec 19 also gets my vote - with the new upgraded light, it's good to grow most plants, it has a nice swimming footprint for fish, versatile scape footprint - my favourite Spec scape is one that is viewed longways from the narrow end (only way it fit, at first I wasn't that keen, but it grew into a surprise), loads of filtration & sponges that last years, all the hardware is hidden behind the black wall
In comparison the Flex is a completely different market, fun colour LED, but significantly lower build quality (than Spec)
Edge is very nice aspect but less convenient to work in & need to upgrade the LED (swap the 46l version LED into the 23l ) if you want to grow anything other than Anubias, java fern etc & unlike the Spec has limited filtration volume (works fine if you stock "normally")
I consider the Chi too small a footprint for even shrimp, unless you go to the 19l & then I'd just go Spec, if you need that small footprint, most people instantly upgrade the LED
The Flex mini is higher quality as well - light is very stylish & I love the swing arm
Understanding what's in the kit & considering if it meets your goals is the key to success with these AIO tank, they are only economic if you don't instantly upgrade the individual components
George Farmer did some very nice scapes with some of the AIO kits (just check his "Thread" history to find them quickly)