UPDATE
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I am just about to commit to the S5. Tested on several rides, it requires roughly 3W with everything on, including the screen in full daylight, which my dynamo hub has no trouble supplying (shimano hub and forumslader charger).

I am more than pleased by Locus maps which connects to ANT+ sensors and supports custom displays.

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I was in the "dedicated GPS" camp but am reconsidering as the Garmin unit is unreliable. As I am in the process of installing a dynohub, power is no longer an argument. If I were to ride in exotic locations it would be Garmin Edge, but since for the short term it'll be North America and Europe, extensive map coverage is not critical.

Before I commit to this change, I'd like to read about the workflow suggested to design and ride a course, or any other relevant consideration. For example, (how) do you use Google Maps, or which other navigation app.

The context is 60+ days where I see myself pulling the proper course from a menu and getting under way, with or without wireless data access.

The biggest issue with Google maps, is there are countless places where I ride - Maine, upstate NY, New Mexico, where there is no cell data connection. Yes you can port down as cache, some maps, but I'm mostly wondering why bother.

The 2nd issue and possibly a major one, is are you going to be OK with the battery life on an Android unit ?.

I was happy enough with the 17 hours on a dedicated GPS, as well as maps on the unit, to choose this route over an app on my iPhone.

Expensive option though and on-phone may work in most cases.

Don't.

I have

• A Galaxy S5 Sport
• A SON28 dynohub in a 700C wheel
• A USB Werk power supply. The E-Werk is one of the most efficient, and in theory the fixed voltage USB Werk should work as well.

Combining them if I don't put my phone in ultra low power mode which precludes running applications, my S5 may or may not remain charged with the head lamp off, and when the road isn't dead flat it goes in and out of charging mode with the screen waking up every time that happens. Without the dynohub it's a lost cause - I've run out of battery in a couple hours, keeping the app stopped and GPS turned off except when needed.

Therefore when I started riding farther I settled on a refurbished Garmin Edge 800 ($170) to have maps (Open Cycle Map derived) to go with my routes. It's not very power hungry, and actually charges at night when I'm running my Edelux ii. The Touring uses the same hardware and the 810 just adds a Bluetooth 2.0 interface; although that's meaningless for figuring out what will also work well navigating because Garmin's problems are in their software.

Before that, I bought and returned a Garmin Edge 810 ($300). I experienced spontaneous power-downs and truncated .FIT files even with the latest firmware. Other people have crashes in round abouts where 800 users are OK.

Before that, I bought and returned a Wahoo ELEMNT ($320). While it displays courses on maps, it doesn't alert on CoursePoints from .tcx files, show the next ones, or indicate distances to them. Turn by turn was not delivered in Q1 2016 as scheduled. The maps do not have street names as in the marketing material. Good minor roads for cycling are invisible when the map is zoomed out, and it cannot pan like a Garmin. I also had problems displaying and recording power.

The ridewithgps application can download map tiles from a variety of sources (notably the Open Cycle Maps) so they work off-line.

The dynohub would theoretically address that issue.

Riding far enough to need GPS I found my phone unusable as a bike computer without the dynohub, and with wouldn't rely on it for a long ride involving significant time riding in the dark.

I reviewed the low cost (free to try) Osmand app. It downloads and stores regional Open Street Maps, so it doesn't need a cell signal.
My review post is here.

I saved a route file from ridewithgps.com onto my android tablet. (I think I used a .gpx Track file.) As I remember, it was a little confusing to figure out at first, so try this well in advance. But the track worked fine, showing as a colored line on the map.

The Galaxy S5 is waterproof and sweatproof. I keep mine in my back jersey pocket with no protection. Very convenient.

But the charging port is not waterproof. And I don't think the screen is very visible in bright sunlight. Those would be the two downsides to using this on the bike.

The BT system is exactly why I like the 810. Seeing that you posted in another thread that you don't use Garmin Connect, I can understand why BT possibly has little use for you.

As a Connect user, I find the BT connection to port a ride up to Connect, or to get a routable map to the device from Connect, to be two very useful features and were primary reasons for choosing this unit over an 800 or 520.

To each his own though and I use this device fully aware that Garmin has a reasonably mediocre reputation in many respects for poor software implementation. In my mind I remain still skeptacle as well, but so far have had mostly positive experiences.

Thanks for the feedback.

I am a bit surprised to read that your SON+eWerk couldn't keep up with the S5. Then I did some research and:

The S5 battery is rated at close to 11Wh. The maximum discharge rate yields 220 minutes, or roughly 3W.
The Garmin Touring is equipped with a 3.7Wh battery that is drained in, say, 8h, so that would be .5W.

Considerable difference indeed.

So, I guess, count me in the (somewhat frustrated) dedicated GPS camp...