I recently entered the Air realm. In the fall I got a MacBook Air and then for my birthday I got an iPad Air. They are both light, fast, and pretty to look at.
The MacBook Air was, ostensibly, a work purchase. My previous job had spoiled me with a MacBook Pro as my primary computer and my current job insists that writers need an 8 core desktop PC to do their work. I disagreed and took matters into my owns hand. I got the entry level Air with beefed up storage. It is more than powerful enough for basic needs. I haven't tried any hardcore games or video editing, but everything else runs quickly and smoothly. I have played with iMovie and that is as smooth on the Air as it is on my wife's Pro.
The two most impressive things about the Air are the battery life and the speed at which it starts up. The weight is great, but with a name like Air it is expected.
I have run the thing for a full day without charging it and not gone bellow ten percent battery life. These runs didn't involve a lot of video watching or even too much use of iTunes, but the wireless was always on and e-mail, calendar, reminders, and Safari were constantly running.
The start up time is impossibly fast. It is easily less than a minute from shutdown to fully functional. At start up, my Air loads calendar, reminders, and e-mail. From asleep to ready is instantaneous. It wakes up as fast as my iPad or iPhone. That is impressive.
The only drawback to the Air is the limited storage. I am not sure I could use it as a primary computer without running out of space. I have a large iPhoto library and a mid-sized iTunes library. I could currently move everything from iMac to the air, but the air's disk would be over 90% full. I could get away without moving up the music since I have iTunes Match, but I would be uncomfortable.
The iPad Air was actually H's idea. She wanted an iPad, but didn't want to buy a new one. She encouraged me to upgrade so she could inherit my iPad 3. It has been a successful swap. She enjoys the iPad 3 and I got a new lighter and faster iPad. The iPad Air is a lot like my old iPad except that it is much faster. The speed is noticeable between the 3 and the Air. Things on the Air are just smoother. The Air is also much thinner and lighter. The cut in weight has been great. I never got tired holding the 3 for long periods of time, but it was definitely a two hand job. With the Air I can comfortably sit on the couch and read with one hand. It is not a easy to one hand as a mini, but, for me, the extra screen real estate is a good trade off. I'm not so convinced that the extra thinness is a great thing. At first the edges didn't feel great while I was holding it and typing in bed, but I've gotten used to it.
One thing that I have noticed that isn't great about the iPad Air is that the screen occasionally feels plasticy. The two older iPad, and Bug's mini, have more solid feeling screens. It is not that the Air's screen is bad, it just sometimes doesn't feel as lush to the touch.