I am using the Spark hardware and like it a lot. All the kits since 1.4.1 and even most of the user kits sound really great. I really like the way that you can tweak your sounds and gets great results within a very short amount of time.
Nevertheless I encountered some things that could be improved...
1. The display reacts a bit slow -
I wish you could improve that with a future firmware update.
2. My MPC Quantize Algorithms are sorely missed. ATM I do that in Logic but if I could have that instant J Dilla / Flying Lotus oddness on the fly in Spark would be really cool.
So please add some more quantize modes (MPC 2k, MPC 60, ESP 1200, Korg DDD, etc.)
3. Found a small bug. When I switch from Instrument 1-8 to 9-16 by pressing the button on the hardware the view on the screen sometimes doesn't switch.
Any improvements would be really appreciated!