A Garmin has been required equipment on all of the Santana tandem tours we’ve taken. We’ve used various units over the years and all have caused frustration for my stoker-navigator. We’ve recently switched to RidewithGPS on an iPhone X mounted using Quadlock. So much better than a Garmin. Much better software and features, better screen and viewing, better user interface. Creating, finding, downloading routes is easy, even fun. Using offline maps and other RwGPS tips, the iPhone X battery lasts many hours, and bringing along an auxiliary battery is always an option for really long days. Can’t see us using a Garmin again.