To me the main strength of the MileagePlus Visa Select is the 1X PQM (up to 5,000 miles per year) and 3X RDM on United.com purchases. I also frequently take advantage of the 2X RDM on gas, dining and grocery.
What I am missing by not having the Explorer card is the chance for an upgrade on United award flights.
There should be cards out there that charge no foreign transaction fee and no annual fee, e.g., Barclaycard Arrival World MasterCard (the no-AF version, not the $89 version).