The Meizu C9 is a little better phone than the Yu Ace because it has a better processor. But that doesn't mean Yu Ace can't be considered as it also has a fingerprint sensor plus a better battery.
Processor: The Meizu C9 comes with the Unisoc SC9832E processor which is better than the MediaTek MT6739 processor of Yu Ace.
Battery: The Yu Ace comes with a 4000 mAh battery whereas the Meizu C9 comes with a 3000 mAh battery.
Also, there is a fingerprint sensor in the Yu Ace.
Check Full Comparison Yu Ace vs Meizu C9
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The Meizu C9 comes with the Android 8.0 OS.
Check Full Device Specifications Meizu C9
Yes, the Meizu C9 is a great phone at its price range with good specifications. The user reviews of this phone are also quite good.
The phone offers the Unisoc SC9832E processor with 2GB of RAM and 3000 mAh of battery. It also has a 13 MP rear and 8 MP front camera.
Check its full specifications and user reviews Meizu C9