Are there advantages of dedicated bike computer instead of smartphone apps? I do a lot of road biking. I have a basic Catseye onboard computer for my speed and odometer. But I also use my iPhone to track and record my biking. I've tried a variety of iPhone apps, the best ones being iMapMyRide and Cyclemeter.

As I get more serious with biking though, I'm looking around at the dedicated biking computers like the Garmin Edge. I'm trying to figure out if they are worth buying or not. Rewind the clock back about 5 years and I'd say definitely yes. But these days, with really awesome GPS-capable smartphone apps, I'm not so sure...

Take for example iMapMyRide. You can buy a cheap ANT+ adapter for your iPhone and then use any ANT+ device with the software. Speedometer, cadence, heartbeat sensor, etc...

Also with these apps it does optional Live Tracking so that when you are out on your ride, your spouse (or anyone you want) can look at a webpage and see your progress on a map. You can do this with the Garmin Edge apparently but I think Garmin charges $25 a year or something for that service.

So if I already have an iPhone/Android and I already take it on rides anyways (for emergencies), then is it worth it at all to get a dedicated biking computer? Just about the only advantage I can think of is that the biking computers are smaller (less weight).

Are there any outstanding advantages to dedicated computers that I'm unaware of?
I recently thought that my smartphone would replace my bike computer, but have come to the conclusion that the bike computer is better. 

Here are the reasons.


One is that the phone is much larger.
Second is mounting. (Whether a suitable mount is available depends on the phone model.)
Third, and this is important... is that smartphones are not designed to sit out exposed to hot sun, extreme temps, and rain; all of which commonly occur in serious cycling.
Fourth is ease of use. My bike computer was specifically designed to sit on the handlebars with easy access to most all functions and in typical cycling conditions. The smartphone is not.
Fifth, my smartphone is important to my professional life. So, having it destroyed in a bike crash would not be good at all. 
Sixth, definitely battery life; although I suppose this depends on the particular phone. (On a recent century+, my riding partner brought along 3 extra batteries and used them all, for his HTC Evo...and my bike computer was still humming along at the end of the day)


A few months back, I bought a smartphone handlebar mount and case which all looked fine in the comfort of my basement. Anyway, once on the bike and in real conditions, it was unusable. The worst thing was that in the glare of sun, I couldn't even see the screen. Also, changing functions was a pain because of the case. Anyway, I rapidly went back to my bike computer. 

BTW...I do carry my phone with me and use Endomondo. However, the phone stays in my jersey pocket; but for typical ride data I use the bike specific computer.