Welcome brother for your question!
Actually there are many CHONDA brands as you named and also add some more like
- Ghani 2. Ravi 3. United 4. Super Asia 5. Super Star 6. Super Power 7. Unique
one thing you have to keep in your mind that all these use China engines.
Secondly they purchase the parts from almost same dealers.
Now if you see METRO, see its engine side covers, they are made up of plastic.
Like wise see the quality of other bikes by seeing their PART'S POLISH in context with the HONDA CD70, Battery (AGS, EXIDE etc?), Tyres (Servis, Panther etc?) their service centre, dealership for aftersale service.
After comparing all these you may purchase UNIQUE 70, RAVI 70, GHANI 70, ROAD PRINCE 70.