Stowe Boyd’s detailed review of TripIT is well worth a read.
Sounds like TripIT provides some of the features I wish Dopplr had – including the ability to pull travel information out of the confirmation emails generated by the airlines, as well as more granular (hour by hour) info about overlaps in your travel with friends.
All they’re missing is the obligatory elided-vowel-of-web-2.0, which I think would make them TripT.
Will this be enough to push a switch to TripIt? I’ll let you know once I get my invite. ;)