I'm torn - I like it as I can search CX, LH, and others that don't show up with EF (right?) - but with a tiny bit more work, I can use those airline sites to find availability. But I'm lazy, and I like the KVS app...just easier to click a button vs. re-doing searches w/EF.
Maybe I'll just let KVS lapse and see if I'm missing anything. The loss of availability, combined with lack of UA visibility, kills off 90% of my searches.