Are you playing live, or just entering notes into a DAW or Notation app? Do you want it portable, to go in a bag with a laptop, or will it sit on a desk? How many octaves do you need? Do you want a quality, realistic action? Do you want knobs and sliders to control MIDI CC events?

There's no keyboard that will work better or worse "with GPO5" than any other. Any USB-MIDI standard keyboard will do the job. You might want one with a foot-pedal to control legato/sustain, if you're playing live.