I went the other way for two reasons:
1) Dolphin uses the stock browser's rendering engine, which is not updated as often as an external one. For older devices is not updated at all. I remember two or three updates in an year on my tablet, which went from 4.4.2 to 5.0.2. Opera is updated in sync with Chromium/Chrome.
2) Opera has text reflow and that made me ditch Dolphin instantaneously. I checked it again now and Dolphin still doesn't have text reflow.