For pvm I'd get Botd + Death unless you like fixing your weapons all the time. Also, even though they don't quite have the damage of Grief + Last Wish, they give more than enough for pvm--including ubers. You can even get by with Oath + Death. I used them in ubers until I got around to upgrading to Botd.
True enough, but at x2 it adds up. And if you happen to trade for something like a Last Wish, there's a decent chance that one of your asylum escapees has put it in a superior. I personally just find it annoying to have to repair in mid-run period. And for anyone that can't get through the game with Botd and Death, 2 x Grief isn't going to help. In the ubers, it will actually slow you down unless you focus all of your other gear on CB.