I had a chat session with Garmin and was told that none of their units, both cycling specific and handheld gps were compatible with uploading from a phone or tablet.
Well, it depends how you interpret it, but they're wrong
Fundamentally, a phone or tablet is just a computer. If it supports USB OTG ("on the go") then it can act as a USB host, meaning that you can connect things to it and access them as mass storage devices.
If the Garmin device in question uses a MicroSD card then it's easy: you whip the card out, stick it in a card reader in the USB port, copy a GPX to the "/Garmin/NewFiles/" folder, and then pop the card back in the Garmin. Alternatively it should be possible (even on Garmins which have no SD card) to plug in the unit itself, mount it as mass storage, and copy the file in the same way.
Essentially, it's exactly what you would do with a computer. You just need a computer which can act as a USB host, and not all phones and tablets can.
I've not used one of the newer Bluetooth-enabled Garmin units but as far as I'm aware you can use a phone to get routes onto them wirelessly; it's just that you have to go via Garmin Connect. (Ugh.)
The Wahoo is certainly excellent if you use one of the apps that it integrates with. I've not tried it with routes from other sources, but as far as I'm aware it should work as you want (push the route to the app, which sends it to the phone). The potential fly in the ointment is whether you can easily get hold of the routes on the phone: eg I use RideWidthGPS for all my route planning, but I'm having to write a tool to get those routes in GPX/TCX format on the phone. Their app won't export to the filesystem (it can download routes but they're saved in a larger JSON object) and their website is essentially unusable on a small screen. Obviously with the Wahoo/RWGPS pairing this isn't an issue, but with Garmin/RWGPS it is, and with Wahoo/SomeOtherTool it may be, too. So I would consider your choice of planning tool: can you get GPXs from it on your phone. (What do you use, by the way: iOS, Android, Windows Phone…?)
Also if you're fussy about navigation I'd ponder the differences between the two. The Wahoo performs well and is very easy to read but it does lack some things that the Garmins have in terms of secondary functionality.
Interesting to hear numerous reports of buggy Tourings. I sold my 800, bought an Elemnt, then picked up a cheap Touring, so I shall see if I suffer the same issues. (And I'll do a few rides with both the Elemnt and the Touring running.)