I would have speed and cadence sensors on both bikes. I realize GPS doesn't care where it is positioned, but I would still like to track the actual kms ridden on each. This is helpful information to know when you may want to service the bike among other things. I take it that most of these units you can probably have two profiles setup and just select the profile you want when you are going to ride.

Comparing Garmin to Wahoo, the Garmin looks harder to setup and program, relying on the buttons instead of the phone app like Wahoo. Seems like the Wahoo Bolt does GPS as well (albeit not in colour like the Garmin 520) and has turn by turn navigation. I am just wondering if this is redundant and using a phone with GPS would be nearly as effective. I have only ever had basic cycling computers, so I am still learning what features might be useful to have.