Opera spent a lot of time and money getting their act together with the spiffy new Webkit version of Opera Mobile. But their users are a hard-to-please bunch, and apparently some weren't completely sold on the new design. So the older version of Opera Mobile is back in the Play Store, sporting the title "Opera Mobile Classic," for one last tour of the browser circuit. It's free, as always, and comes with the original's comparatively wide featureset. It appears to be compatible with devices running Gingerbread and up, and possibly more.
The newer version of Opera is faster and objectively better in just about every respect, but old users might be missing the original syncing via Opera Link, Speed Dial, text rendering, and a more (ahem) familiar user interface.