I also have same question. We need call recorder
ACR works fine. I tried a lot of other "call recorders" but none of them work. ACR does actually record the calls and it's ok. Not as sofisticated as built in recorder in windows phone 10 but it does the job. But you have to pay for it.
I use an app called "Call recorder", it works perfectly, records all my calls faultlessly.
the developer is - olympic.game.studio (at) gmail (dot) com.