Used it in DTW about a month ago...

Tried from every possible angle and it wouldn't work. Did it partly for the novelty and partly because I didn't have access to a printer...and saved some time of finding a kiosk once I got to DTW.

In the end, wasted more time because I waited in line once, spent a little time, holding people up behind me, trying to get it to scan, when it wouldn't, had to go across the bridge to the kiosk, print it, and get back in line (they let me go back to the elite line even though I didn't have the UG yet).

Would I do it again? Sure, but I'd probably try to have the paper one handy