A simple but solid solution
I needed a simple (but high-quality) MIDI/audio interface to support a Hauptwerk virtual pipe organ installation. After investigating units from Focusrite, Behringer and others, I chose the Steinberg UR22 because it was inexpensive, easy to connect and install, used a standard USB 2.0 computer connection, included MIDI in/out ports, and can operate independently of the available Cubase AI software. The UR22 is compact, but built like a tank. Since it is bus-powered (no external power supply), and I'm using it with a MacBook Pro, I was concerned initially about energy drain from the laptop's battery; but thus far, that has not been a significant problem. In operation, the UR22 accepts live MIDI input from a digital organ, then converts the digital audio stream from Hauptwerk software to analog audio, which it feeds back into the organ's sound system. Beyond this, the unit is essentially invisible - which is exactly what I needed. Clean sound, simple operation, MIDI integration, solid construction - if those are your needs, I can highly recommend the Steinberg UR22.