Both the phones have their pros and cons,lets analyze:-
Advantages of Samsung Galaxy On5
1.More RAM:-More RAM means more applications can run at the same time,
2.Bigger Screen:-Reading, browsing internet and watching movies is more pleasing experience on a bigger screen.
3.Better Screen Resolution:-More resolution means sharper and crisper screen.
4.Better Camera Resolution:-More resolution generally means better picture quality,
5.Bigger Battery:-It can generally last more time.
Verdict - In my opinion,Samsung Galaxy On5 is better overall performance and price
You can also compare these devices on 91mobiles
Let us analyze the pros of On7 Pro:
Galaxy On7 Pro provides a better 3000 mAh battery as compared 2600 mAh battery in On5 pro. Better battery is always a plus point as the user can use the smartphone for a longer period of time.
On7 pro comes with a better screen size (5.5 inches) as compared to 5.0 inch in On5 pro. The bigger screen enables the user to multitask between various apps easily, also you can watch movies and videos clearly.
On7 Pro comes with 13 megapixels (MP) camera resolution than Samsung Galaxy On5 Pro (8 MP). Samsung On7 pro provides a much better camera performance in both outdoor and indoor condition in comparison to the performance of Galaxy On5 pro.
On7 Pro is a much slimmer smartphone than on5 pro. This give On7 Pro a much better in hand feel and a better overall look.
Only things that help On5 survive the competition is that it is lightweight
Samsung Galaxy On7 pro is in a win-win situation here.
You can check the details using the following link Samsung Galaxy On7 pro vs Samsung Galaxy On 5 pro