I love it overall, but have found the time saved varies wildly by airport.
Departing
MIA - fantastic, 45-60 mins
PHX - good, 20 mins
JFK - good, similar
EWR - useless, all lines mixed up
Arriving from abroad
MIA: still fantastic
LAX: almost as good
PHX: good
JFK: good
EWR: so-so (not busy the couple of times I've been through with GE)
Moral of the story
Avoid EWR
