I recently got a Wahoo RFLKT+ and BT Cadence sensor. I haven't gotten to use it that many times yet, but my initial impression has been very positive.

I tried using my iPhone itself as a bike computer before, but the screen being on all the time really drained the battery, much worse then the GPS with the screen off, so for a while I had my phone running STrava with the screen off in a pocket and then a plain old bike computer so I could see my current speed, distance, time, cadence.

With my new bike I decided I wanted to try the Wahoo route so I could get more data in to my phone and not buy an expensive Garman I need to worry about charging, etc. The Wahoo RFLKT+ lets me get info on a display without running down the battery too much.

So far my only complaint was since I got the cadency only BT sensor, not cadence and speed, the RFLKT+ shows the last received speed from the phone for a bit when you stop, instead of showing 0. Minor annoyance, but if I could do it again I would get the speed and cadence sensor.

If this works well I will probably not use a regular bike computer on this bike. If not I may get a computer and use Strava separately on my phone.