My preferred GPS(s) are Garmin 400T and 600T units which also work nicely for off-bike hikes and such -- both loaded with Open Street Maps. Despite a GUI that seems weird and awkward to me. I like the dedicated GPSs for their ruggedness, waterproofness, and water resistance and have backup navigation apps and maps for my phone, which I try to reserve primarily for comms and photography when I'm riding; when in lodging or have a fully charged power bank, the phone becomes my laptop substitute.
The mounts for these Garmins use cable ties, so are suitable for all handlebars and can even be oriented the long way, opening possibilities for centering on a stem or top tube. I have mine mounted on the fore-aft extension of the Thorn Accessory T-bars on my Nomad and Enduro-Allroad bike and on the handlebars of my randonneur bikes.
All my bikes are fitted with separate robustly wired bike computers, which I have found more reliable than wireless. These all have at minimum pace arrows, average speed, top speed, current speed, trip distance and total distance. Some have additional features that while fun, I find aren't really necessary. The bike computers nicely complement the navigation capabilities of the Garmin 400T and 600T. If you go with the Garmin hiking-oriented GPSs, be aware the company really doesn't support them for very long -- about 4 years from introduction. I find the heat and UV of my desert tours cause the rubbery plastic over the power buttons to perish, but an eBay seller in Russia has come up with a factory-looking replacement that super glues in place and restores waterproofness and function to new. Once upon a time, I invested in a full set of Garmin maps, but have since found the Open Street Maps (and their sometimes cycling-specific variations) to be as good as Garmin's if you also download topographic and shader overlays. Russian maps are also very good and highly detailed. I also carry paper maps and a good orienteering compass with me and know how to use both in case the electronics fail.
Best,
Dan.
