If you are looking for a taurus .44mag, I would recommend the raging bull. You aren't going to break it, and it can handle any hot loads you put through it, including the factory .44mag +p's that are out. My RB is in .454, and that is a great gun.
I also have the .444 ultralite, and it has given me some problems. After opening it up, and doing some sanding, it works great now, shoots really good.
The trackers I dont know about, and I have heard a couple of stories with problems with them, but then again, there are plenty of people out there who love them.
A couple of things to make sure of on taurus:
cylinder to barrel alignment (use a pen flashlight)
tight lockup on all cylinders
firing smoothness
Give it a good test run before you buy it, and you'll get yourself a good gun.