Heart rate monitors for Cycling
Interesting and personal topic.  I'll ignore your budget for now...

Ok i make use of a Garmin Edge 1000 with a HR monitor.  I like to monitor my HR by % of max rather than beats.  Makes it easier when looking at zones thinking of it in %.

For a indoor training on Zwift i use the Wahoo Kickr you refer to above.  Now here it records in beats since thats what Zwift shows but whats good here is it supports Bluetooth and ANT+ 

Different tools for different applications.  

On the bike Polar works fine easy enough to upload and you can see tour zones, HR in beats or %.  Garment n provides a few more options like routing, HR graph even these days on the edge 1000 and 520s.

Coming back to your budget... The Wahoo kickr is a simple cheap option to use with your phone if you only using Strava.  If your using other apps like Garmin connect, Polar etc a dedicated monitor and strap has more advantages.

But you pay for those advantages.  I guess flexibility and compatibility are the major things to consider.