I have used truecaller in both android & Iphone.
The truecaller for android is an amazing app. It has the live caller id feature which shows the caller info before you take the call.That is very useful. It can also block any caller shows spam caller. I recommend every android user to download this app.
For Iphone user it is a waste of app. For the security reason of ios it does not shows live caller id. Without that the app is waste. It can only shows after you take the call. You just have to copy the number & paste it to truecaller app. Not useful.
Verdict: For android user it is must have app, not recommended for iphone user.