I have the Elemnt, which has the same functionality as the Bolt. Battery life seems pretty good. My wife has the Edge 520 plus.
The one really big advantage for the Bolt is that initial setup is much easier than on the Garmin due to the phone app. Also, the interface is simpler and a bit cleaner. However, part of the reason that it’s simpler is that the device is simply less powerful.
Once the device is set up, the Edge has some definite advantages. The maps are simply better, no comparison. On the Edge, you can configure the level of detail at different zoom levels, color gives you more information, and you see the street names. On the Wahoo, no street names and when you zoom out the map becomes pretty much useless. The maps are just graphics, unlike the Garmin, which has actual map data. Navigation of loaded courses works pretty well on both, but Edge has the advantage here as well. It can actually navigate back on course if you go off it, whereas on the Wahoo you’ll need to pull out your phone. We recently downloaded the same route for an organized ride. It turned out there were no cues in the file, so I was out of luck, whereas the 520+ figured out the cues itself on the fly. We haven’t loaded any Garmin IQ apps yet but some of them look interesting and Wahoo has nothing to compete with them.
The Edge has activity profiles, which gives it some power that the Wahoo lacks, but they are a mixed blessing. I think the profiles are the source of a lot of frustration with the Garmin since essentially every single attribute can be changed for each profile so if something’s not what you want it can be frustrating to get the profiles properly dialed in. They definitely increase the complexity of the device. The Wahoo doesn’t need profiles as much since configuration is easier with the phone app, but I frequently find myself riding with the wrong screen configuration since I can’t be bothered once I’m ready for a ride to pull out the phone and fiddle with the settings for the kind of riding I’m doing (MTB/road training/road navigation/racing).
The Wahoo has been very reliable and I’ve never lost a file. It had some bugs early on that got fixed. The main problem I have now is with the live tracking which never seems to work for me. We have less miles on the Garmin but it’s also been very reliable. Only glitch so far was one course stopped navigating in the middle of it.
If you don’t mind fiddling with a device that’s more complicated but more powerful, navigating courses and maps are important to you, and the IQ apps provide functionality you want, the Garmin wins. If you prefer a simple, clean interface and your needs aren’t too advanced, you may prefer the Wahoo.