I have used Dolphin for years and ditched Opera a long time ago. https://play.google.com/store/apps/details?id=mobi.mgeek.Tun...
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.
Maybe they don't apply to Jetpack. Do you know if they have a bug tracker?