This is a great set. The first box set I bought and it has seen some heavy rotation.
As far as I know Edith has only been released paired with RR&Panic. Probably there's an expensive Japanese issue for money that buys you several of the twofers though.
The VME of Domino features some stuff not in the box, otherwise, the box is the way to go. Kirk is a master and each alternate take is actually more than just another recording to correct mistakes, it's usually a completely new & original rendering. Just compare the solo on the two versions of Blues for Alice that start of the box and which are both included on the We Free Kings CD. The guy way AMAZING.
The box was offered by zweitausendeins at an abysmal low price in the past, which means you may still find it at a good price. This seller from amazon marketplace has a set for 116EUR, add 14EUR p&p to that to make a total of some 155 US$ delivered to your doorstep. Quite a good price for an 11 disk set, I'd say. I paid more for mine, much less for a zweitausendeins copy for a friend though.