Garmin Edge 510 v Strava app

I spent £100 on an Edge 200, and I thought that was overpriced until I got to grips with the 'courses' functionality. (Everything else works fine, but £100 for a bike computer is a bit pricey) We're away in Anglesey next week, and provided my slightly dodgy knee plays ball, I'll be riding in completely unfamiliar territory, but because the route is laid out for me, I'll have a blast.

In practice, I often record the ride on both the Garmin and the phone, just because uploading from the phone is way easier than booting the laptop and plugging the Garmin in.

Between my wife & I we have a Garmin 800, 500, 205, Dakota and a couple of android smartphones (LG G2 and Galaxy S2). The Garmins tend to be more consistent in their data collection and I'm fairly confident we can trust the output the vast majority of the time, whereas the phones can create quite some anomalies now & again. Since a Kitkat "upgrade" for example, my LG G2 for has been adding approx 10% to all my mileage in Strava so I'm having to exclusively use the Garmin 800 data from rides until I can fix that.

As above, the Garmin's aren't perfect, but then I don't think 100% reliable GPS tracking exists (outside of the military). If I had to choose though, I'd take a Garmin any day over the phone, although the latter is admittedly a convenient and cheap option if you already have a smartphone.

Agree with the first post, as for dedicated GPS being more accurate, I've heard this from someone who works in that line of work. I've used view ranger,Strava and my 800 edge. The edge wins hands down but it can still have it's blips of erratic data.

Why not a Bryton rider series cheaper and just as good and leaves you with a phone to contact a friend when you get stuck.

I agree with bashthebox except the accuracy thing is a fallacy. Most phones are easily as accurate as a Garmin. However some apps running on the phones do not collect/present the data accurately. I'd pitch Viewranger on a phone against Garmin for accuracy any day.

Yup.
ANT+ means you can use the speed/cadence unit and a HR monitor.
More accurate GPS for the all-important Strava segments.
Long battery life, meaning your phone's not dead when you get lost and need a map.
And of course you have a readout of speed, time, distance etc right there on your stem.