On Jan 23, 2018 DJI introduced a new drone to its consumer lineup, the DJI Mavic Air. Product-wise the Mavic Air sits between the smaller DJI Spark and the DJI Mavic Pro. The Air is in many ways a much better drone than both of those products.
While it has the same camera sensor as the Mavic Pro, it however records with 100 mb/s instead of 60 what the Pro does. This is a significant upgrade and produces videos with less compression and higher visible quality. Anybody who used the Mavic Pro before knows that especially with 4K, the image quality quickly falls apart.
It also looks that when folded up the Mavic Air is even smaller than the Spark, because the Spark doesn't have foldable legs. If price isn't any concern for you, you should not consider buying the Spark anymore. Apart from the price I don't see any upsides to the Spark. It is the much lesser product.
But the Mavic Air even makes the Mavic Pro a hard-sell now. Apart from the longer flight time, which can be offset by just having more batteries, I don't see any other advantages over the Air.
Even though the Mavic Air looks great and seems like an awesome drone, I am holding out for the update to DJI Mavic Pro sometime this spring or summer. My guess is that DJI will give it the better camera processing, 16 GB internal storage and the rear collision detection sensors, at least they should.