Since Opera went down the Chrome route, I've been using Maxthon. I've found it to be a little faster than Firefox, and with very few crashes. Maxthon does have a lot of skins, but not many extensions - for that, Firefox is unbeatable, and much better than either Opera or Chrome.
Opera 26 has I think, still got quite a long way to go before I can use it as my main browser.
If you are looking for a browser that's like Opera 12 you might like Otter - http://otter-browser.org/