I'm really stuck between some features/tools of the ELEMNT vs the Garmin 820. I've read DCRainmaker's reviews and understand pretty well the pros and cons of both. I'll list what I like/don't like about each below. I'd be very grateful for thoughts, advice, etc.

Functions To Be Used

• Manage indoor trainer workouts (like the Garmin can do)
• Track HR, power, speed, distance, etc data from rides
• Integrate with Strava smoothly
• Navigation, ideally with advanced routefinding like the Garmin unit has

Sensors

• Polar H7 (Bluetooth Smart) HRM
• Stages Power Meter Crank (Bluetooth/Ant +, will be buying soon)
• iPhone 7 Plus

Pros/Cons
Garmin Pros

• Can do all functions I'm interested in

Garmin Cons

• Doesn't work with Polar H7 HRM I already have, would have to buy ANT+ HRM
• Finicky software, after reading reviews, especially with WiFi connection to upload data post-ride

ELEMNT Pros

• Works with HRM I already have
• High-contrast screen works well outdoors in bright light
• LED notifier lights are nifty/helpful

ELEMNT Cons

• Can't manage structured workouts

So, three core questions: first, of the two options above, which would you buy? Second, are there other options besides these two I should consider? Finally, what ANT+ HRM straps would you guys recommend? I'm bummed I won't be able to use my Polar as I use it for gym workouts/lifting weights/etc. My phone obviously can't use ANT+ so it's annoying to have two HRMs if I go with the Garmin + a new HRM.