I'm happy with the following combination:
- Favero Assioma Uno (pedal type) power meter
- Wahoo Tickr (chest strap) heart rate monitor
- iPhone SE
- Wahoo Fitness iPhone app
- Strava paid subscription
- Elevate Chrome extension for Strava (!)
- Sauce Chrome extension for Strava
The Favero pedals have worked great for me. Easy set-up. Easy to move between bikes. Affordable. And I can upgrade to Duo if I decide I want right leg data too. The Favero pedals nominally use Look Keo type cleats. Before I got the Favero pedals, I used Look Keo Blade pedals on my main road bike. So, when I got the Faveros, I transferred the Blades to my commuter bike. I actually slightly prefer the Faveros to the Blades as pedals... but the bigger difference is that Favero brand cleats are clearly superior to actual Look cleats. Evidently made from better material, they're much longer wearing.
IMHO, Elevate's Fitness-&-Freshness feature works much better than the one in Strava.
The iPhone actually works great as a cycling computer... even for long rides. I like being able to see/hear my phone (and text messages) while I ride. On really hot, summer days the iPhone can overheat, so I move it out of the sunlight. I sometimes use an Anker Powercore Lite supplemental battery. With that, i can go days or hundreds of miles without plugging into a wall. But again, on hot days its important to only charge the phone for short periods (like maybe 10 or 15 minutes) to keep it from overheating.