Private car service
Private car service is the cleanest IAH to Galleria option when the trip ends at a hotel canopy, an office tower lobby, a residence, or a restaurant rather than a transit stop. The value is the plan, not just the drive: flight tracking, a named baggage-claim pickup point, a confirmed sedan or SUV, a stated wait policy, and the exact Uptown entrance, all settled in writing before the plane lands.
Taxi from IAH
Taxis load from the arrivals-level curb outside baggage claim, which makes them a reasonable walk-up option if you land without a plan. The tradeoff on this particular route is distance: the Galleria is a long cross-town drive from IAH, so the metered fare floats with traffic and you will not know the number until you arrive.
Rideshare from IAH
App rides work from the arrivals curb at IAH and suit flexible travelers with light bags. The route's weakness is that everything stays unconfirmed until you land: the vehicle that shows up, the surge pricing during arrival banks or storms, and the curb shuffle while you find the car. For a hotel check-in or a meeting, that uncertainty is the cost.
METRO 500 Downtown Direct plus a transfer
The 500 Downtown Direct is a legitimately good airport bus: nonstop from Terminal E Door E-201 to downtown Houston, every 30 minutes, $4.50 flat, with coaches that carry overhead luggage storage. Its limit is geography. It serves downtown, and the Galleria is on the west side, so Uptown-bound riders face a downtown transfer with bags before heading back west.
Rental car
A rental only earns its keep when the Galleria is the first stop in a self-drive week across greater Houston. For a single transfer to an Uptown hotel or office, the rental shuttle, the counter, the tolls, and Galleria-area parking usually add more friction than a confirmed car at baggage claim.