I haven't used the Schwalbe - I'm sure it's a quality piece.
As Denomerdano noted the guage on the SKS is really handy. The function is really well thought out as well.
I've owned a lot of SKS products over the years (a few pairs out of the 4.1 million sets of full fenders they make in Germany per year and a couple floor pumps for examples) and the quality is always great - and it's all in house.
So yeah, you probably can't go wrong either way (and I'd prefer a system separate from my floor pump) but I'd buy the SKS based off past experience.