I bought the Olloclip lens set for my iPhone 6 and found them to be high quality and useful under certain cirumstances. The main issue is that I’m hardly without my DSLR and 99 times out of 100 will simply use that instead of my iPhone. I just got the iPhone 7 Plus however and have been really impressed by the portrait mode and the general quality of the camera which is quite outstanding. Gottabe Mobile have reviewed the latest iteration of the Olloclip system for the iPhone 7 and it’s a comprehensive and useful synopsis that should help if you’re considering getting it yourself.
You can find the full article here – https://www.gottabemobile.com/2016/12/11/olloclip-for-iphone-7-or-iphone-plus-photography-review/