I used to love Seal Rock. For one content patch in the 3.0 cycle, spamming Seal Rock was practically all I did X). I can't stomach shatter, tried it a few times and it seemed like a PvE mode wherein the opponent is a slab of ice that doesn't fight back. The few times I played, we barely had any contact with the other teams. I suspect that's why some people like Shatter though. Now I only queue for the Feast which is easily my favorite PvP mode, over Seal Rock even. The Feast is pretty much the highest tier endgame for PvP, albeit I haven't started doing ranked yet. Given that the queue times for The Feast are so fast, I wonder why people don't mention it more often.