I understand this includes two spare batteries, a spare set of props and a few other things. Do people here think it's good value, or should you just go for the quad alone and buy the extras separately?
You can't really fly with just one battery. If you only want two, it's not worth it, obviously. If you want three batteries and this is a good number, the FM package comes out to $40 more.
In the past I've not put much value in the charging hub, I usually end up buying the aftermarket charger that charges 3 batteries at the _same_ time. However, I like the design of this hub as it's very portable. The aftermarket chargers are very big. With the Phantom and even the Pro, this is not been much of a an issue. However, I got the Air because it's _very_ portable. So I probably won't go with the larger charger and stay with the hub. It folds up very small.
I also like the addition of the Power bank Adapter. I can see this being _very_ useful. You take a used battery and can charge the controller or other device with it. You will end up with a depleted controller when you need it at some point. But you can also buy a small power bank for about $10 that will do this as well.
You need something to carry the Air. So you will probably end up spending at least $10 or so. I think DJI did a good job with this case but it's not great. What is also nice is that DJI includes a smaller case for just the Air. This protects the props in case you want to do something like put the Air in a backpack. Still, you could find a case for about $5.
Yes, you do get an extra, extra pair of props. To me, not a big deal as you already get a set.
So if you want thee batteries I'd say the FM package is worth it. The items above are _probably_ worth the $40. But some people don't like the case, already have one, etc. and don't want to spend the $40.