The pixels are not exactly plug and play.
They do take some work to be sure you have working strings. Once you have accomplished a working string they seem to work fairly well.
You do get to be good a splicing though. The pixel strings are all hard wired together. I have found that making a cutting template out of a piece of old tie wrap helps keep my cutting consistent. The splicing method I have come to use is butt end splicing. That is accomplished by making a very tiny strip on each end of the wires, tint each end then tape them down on a hard surface butted end to end, then finally gently touching the solder iron to the center between the wires with a tiny amount of solder. That joint then flows together and then you slide a small piece of shrink wrap over the joint and seal it up. I bought a reel of shrink to do this with.
Splicing is applicable for all the elements. Pixels, rectangles, squares and to some extent strips (adding on the connectors/extended wire).
I agree with Steve about spares, particullarly ordering 15 -20% more than you think you need, extra SSCs, TH2010 tester etc.
Discussions here are to solve problems, sometimes they sound terrible but someone usually comes up with a solution. Sometimes its operator error, sometimes it is a simple hardware/software mod that is needed.
I hope this helps guide you through the DIY experience. The end result is quite satisfying.