In my opinion ZTE Blade A2 Plus is best in specifications and overall it has powerful performance.
Check the link here
Micromax Yu Yunicorn vs ZTE Blade A2 Plus
Both the phones have their pros and cons, I think you should go for ZTE Blade A2 Plus.
ZTE Blade A2 Plus has the following advantages : -
1. ZTE Blade A2 Plus has 5000mAh Battery while Micromax Yu Yunicorn has 4000mAh Battery.
2. ZTE Blade A2 Plus Supports VoLTE while Micromax Yu Yunicorn doesn`t (Biggest Drawback).
It is not like that it is a one sided game, ZTE Blade A2 Plus has the following advantages -
1. Micromax Yu Yunicorn has 1.8 GHz while ZTE Blade A2 Plus has 1.5GHz Processor
Verdict - In my opinion, ZTE A2 Plus a better phone in overall performance
You can also compare these devices on 91mobiles. Link - ZTE Blade A2 Plus vs Yu Yunicorn