I am most of the time using Spark with my Mac trackpad (not with its own controller).
I find using Tempo little problematic:
First, it's difficult to give it a certain exact value (for example 100) cause there are those decimals. So it would be helpful to have a chance to type it with numbers from computer keyboard. And/Or, have a setting to just use whole numbers (without decimals).
Another thing would be great to have for every parameter/knob. Pressing for example shift or ctrl etc. and then touching knob/click would not change the value but show it on screen instead.