Leather care and restoration just doesnt' cry out AIO for me. Leather care/maintenance, yes. Leather restoration, no. IMO, leather care/maintenance is pretty simple, vac out the loose debris and clean with a mild soap dilution (no, not saddle soap). That soap can be a light (1:10/1:8) solution of Woolite and water or a leather specific cleaner like those offered by the likes of Lexol or Leatherique. The W&W or Lexol options are more "budget" than is the Leatherique product kit.
You don't mention what age/mileage on your vehicle, but perhaps a thorough cleaning is all your seats require to bring them back.
Leather "conditioning" and "restoration" would involve another set of product discussions.