I think that depends if your workflow is oriented around the keyboard or the mouse. For me it is keyboard oriented and I frequently use (Ctrl)+Shift+Arrows for finegrained selection anyways so Ctrl+C/V is most convenient. I also use Vimium in my browser. If my workflow was mouse oriented I'd instead use Gesturefy.
I think they're equivalent and certainly both are better than using the right-click menu.
I don't always use the mouse, but when I do, I only use the mouse, no keyboard needed at all.
Using CTRL+C/V requires an unholy synchronization of mouse and keyboard. But unix-style middle-click paste is entirely mouse-controlled and very elegant. Of course, if you are inside a text file, you can use vim keyboard tricks that are even faster because you don't need to select the text.
I think they're equivalent and certainly both are better than using the right-click menu.