Yes, I noticed this....it's what you look for to catch malicious apps.
A 'User Report' ..., when they've just had all your clicks & links & have all your bookmarks anyway...
And the User pays for it on their data plan. The app size, data growth, cache & background data is higher than even Google or Facebook....Lol.
What I'm saying is that Opera Turbo doesn't render much better than Opera Mini on Nexus devices (beside interactive js and some other stuff). Marks @200 points in both cases with opera 14 - N7 running Android 4.3. Ain't the same thing running 4.4 on a chinese tablet where the performance is doubled with Opera Turbo. Sounds stupid but it's true.
They do have versions on the FTP site ftp://ftp.opera.com/pub/opera/android the numbers referring to the version number (that is, 3400 is 34.00) ... but you'll note they also specify ARM7 (though of course any later 32-bit ARM processor should work). If you have an older phone or one with a non-ARM processor then I don't know ...