I’ve flown into all the Minneapolis-area airports frequently over the years. The three best options are MSP itself, Flying Cloud (FCM) and St. Paul Downtown (STP).
The only advantage to MSP is convenience; all your customer will need is a ride from the main terminal to $ignature. Be prepared to keep 150 knots to at least the Outer Marker or if it’s a VMC day, be vectored nearly overhead the airport for a slam-dunk approach to 12R/30L. Everything costs more there.
FCM is in a fuel price war there right now, the other day I paid a little over $5/gallon. (I know, still high, but this is Minnesota, Land of 10,000 taxes). Crew cars seem to be readily available and it’s pretty easy driving to/from MSP. Plus in/out of the Class Bravo is well handled by Minneapolis Approach/Departure. Most cabbies know how to get there from MSP, too.
St. Paul is also very easy in and out, but the fuel prices are higher. One FBO never seems to have their crew car available, the other, Signature, always seems to have everything ready to go for you. But they are “The high-price spread” to be sure.
Just some things to consider.
Be safe and have fun,