The rechargeable, hospital-strength workhorse that exclusive pumpers and back-to-work parents swear by, and it's usually covered by insurance.
The S1 Plus is our default recommendation because it's a closed-system, hospital-strength pump with an internal rechargeable battery, so you can pump on the couch or in the car without hunting for an outlet. Suction and cycle speed adjust independently, which makes it genuinely comfortable to dial in a letdown-then-express rhythm. It's quiet, holds output well over months of daily use, and is frequently available through US insurance at little or no cost. Skip it if you want something truly hands-free and discreet, because you're still tethered to bottles and tubing at a machine. The nearly identical S2 (pink, corded-only) is a fine money-saver if you don't need the battery.