I bought the Transition pickup as I wanted something a little more versatile and 'expressive' than the usual high output bridge pickups I go for, to go in my Alder bodied Jackson. I wanted a pickup that did a whole range of tones, that in particular would have a good clean sound, particularly in coil-split mode. I chose the Transition because it's specifically has a lower output than most of DiMarzio's high-output range (it's one of DiMarzio's High Output pickups, but at the lower end of the scale). For the record I'm not particularly a fan of Steve Lukather, so he didn't influence my purchase. The fact that DiMarzio seem to be very competitively priced compared to a lot of pickup makers these days didn't hurt. You can pay half as much again for some other brands out there.
This pickup I feel does just what I need. It has growl and bite when I want it (when playing both rhythm and lead work), but cleans up fantastically too.
On distorted tones it has presence, clarity and depth as well as noticeable string definition. I can't imagine not getting a sound I wanted (with the right amp) from this pickup.
When clean it doesn't sound too bright or shrill (I've had some pickups where the bridge pickup's clean sound will cut you in half), yet the notes are clear and articulate, not muddy.
Looks-wise, DiMarzio's finish is always great, no scratches out of the box (and I've had some new pickups before from other manufacturers that HAVE been scratched) but I was a bit unsure about the look of the vintage style slug/screw polepieces. I tend to like the double Hex bolt look which DiMarzio do on a lot of their humbuckers, but I think the polepiece type/metal is supposed to make a difference to the sound, so that's the important thing and I have no complaints there!