I reverted back to opera mini 7.0.5 (I have the backup of it in my hard drive).
I feel the version 7.0.5 is more comfortable to use;
+it runs better/smoother on my old iPhone 4.
+no need to worry of having accidentally swipping to "discover tab" when on data roaming.
+having ability to edit bookmark's url is a pleasure.
+copying text from websites is easier.
The only downside of version 7.0.5 for me is the UI feels old compared to version 8.0.x
When I need better internet experience, I use safari (it's preinsralled, having good performance and speed, so why left it unused?) so it's a good combo, opera mini 7.0.5 for saving data, safari for full browsing experience.