For having played quite a lot with the two, I like SparkLE a lot more. I find the omission of the screen not to be too much of a handicap. You need to rely on the computer screen for things such as browsing, or knowing which parameters are assigned to which knobs, but once you have your kit set up, and your useful assignations memorized, you really don't need it much.
I like the layout of the controller more, and the step buttons are better placed than on the big Spark.
If both controllers were at the same price, I'd still go with SparkLE, also because it fits in a backpack so easily.