I just got the Domination, and I've seen and heard about the shift.  I was between the two when deciding finally to drill the Domination.  I polled people here and pretty much everyone endorsed the shift as the more versitile and controlable piece.  From what I've seen, this is pretty true.  The Shift being pearl particle rather than pearl reactive tends to be more predictable.  

I however believe that I made the right choice given my situation.  The Domination allows me to play in on medium to slightly heavy oil without any carry concerns.  The Shifts that I've seen however tend to lose energy earlier and can have trouble turning the corner on such shots.  That is not to say that it cannot turn the corner at all, just that the Domination seems to concerve more of its energy for the backend.

The balls tend to give a fairly similar amount of overall hook, so if one were to have a smaller arsenal, I would not get both.  They offer quite different reaction shapes, but given the 3 or 4 ball arsenal something with more separation would be advisable.

If your looking for a three ball arsenal, the T road pearl, Shift, and Special or Secret Agent sounds pretty good.  If you have room for 4 T road pearl, sure fire, domination and special or secret.  The Shift serves as kind of a compromise between the Sure fire and the Domination.  I'd figure that the Sure fire is smoother than the Shift with a symmetrical core design, while the Domination is stronger down lane as I've already mentioned.  Feel free to pm me if you have any more questions.
--------------------
four fried chickens and a coke[/size=4]

Let me say something, let me say something...
AAAAAAAAAAAAAHHHHHHHHHHHHHHHHH