Ha Mike,
I have both, started with a Mavic Pro 18 months ago, bought the Spark 2 months ago, as a backup.
To answers just your questions; yes, the Mavic Pro's camera is quite better, at least it gives you much more possibilitys (RAW photo's, 4k video output, settings to choose different color and sharpness presets, etc. Be aware that this also means much more things can go wrong, and it is exactly what I love so much about my Spark; switch it on, hit record and fly. No worries about all those pesky settings! It provides for absolutely stress free flying. Know though, that a big part of the camera is the gimball. The Mavic Pro's gimball is superior to that of the Spark, and you really notice it; you can fly really smooth shots with the Mavic, where there with the Spark you always run the risk that it reacts a bit choppy.
Range-wise, yes, the Mavic Pro has a range far superior to that of the Spark. In my case, the maximum I have flown my Mavic Pro is about 1600m (in CE mode). At that range, it will give you some warnings when flying low, but nothing real scary. My Spark, I had to put it in FCC mode, otherwise I wouldn't even be able to fly it across a football field! The distance is not such a very big issue to me (even though it can be really cool to fly it at a 1000m away), it is more that the Mavic Pro's is so much more robust. I hardly ever worry about losing connection to the Mavic, whereas with the Spark, there is always this little voice in the back of my head telling me to not fly too far away.
There are many other differences between the two that can matter, depending on how you (want to) use them. Feel free to ask!
I hope this helps!
Cheers, Joost