The Mini will be a step up the ladder from a Spark, as good a little drone the Spark is, plus it's a new version of a drone. In the same way as if you were going to go with a larger drone, say the Mavic Pro, you may not be able to move up to the
Mavic 2 Pro but for the few extra hundred dollars, you would be far better off by choosing the
Air2S over a Mavic Pro for a number of reasons, not least because it is a new version of a drone.
A Spark is the bottom of the totem pole, therefore, if you can afford the little extra, it's better to move up to a Mini or
Mini 2 and if you were in the market for a Mavic Pro, it would be better to move up to the
Air2S than settle for the older, but still very good, Mavic Pro. I started off with a Mavic Pro, so I know what a capable drone that was. I sold it and bought the
Mavic 2 Pro and I've been extremely happy with that, ever since.
I had contemplated getting the
Mavic 3 but now that I see a lot of feedback regarding the new
Mavic 3, I'm going to save the money and stick with my
Mavic 2 Pro, for now. Good luck with whichever you decide to go with.