Somewhere in the range of version 10's there is the "best choice". I accidentally discovered the other day that Dolphin would play YouTube and some other videos in the browser when set to "desktop" mode (Maxthon does the same---or at least older versions did). But not all version 10's are created equal and I'm now going through each one to find the best fit for the types of things that Opera Mobile refuses to do.
More to come.
With the arrival of version 11, the Dolphin browser for Android essentially leaves the Nook ST behind. Pages don't load even though the address bar shows a change in URL, as with many other supposedly compatible browsers, and many other functions that used to work just fine range from clunky to unresponsive. Settings (if you can actually get to them) are often ignored. I don't know about Dolphin Mini but it never was as good as the full browser anyway, IMHO.