I’ve been playing with Epiphany for a little over a month now and just now tracked down an annoyance: Epiphany doesn’t work with traditional X11 Cut-n-Paste.
For those of you not steeped in the traditions of X-Windows, an explanation. When you highlight text in X, it is automatically copied to the clipboard. Clicking the middle mouse button (or both buttons if you only have two buttons) should paste the text. This is quite handy since it means you can do cut-n-paste without letting go of the mouse.