What is what? I am going to guess one is a one wheel wonder and one is a limited slip? Who can help me?

Nope they are both limited slip.

From what I know which some days is a lot and other
not very much, one has the split half way in the splines and the other is full splines. I rebuilt
mine last year as I had the half length splines and
put in the full length from a kit that cost about 180 dollars. If you would like I can send some pictures of what they look like.

Obviously the full length is stronger and less
likely to strip axle splines.

The trac-lock looks like an open, power lock looks like a sure-grip. For mostly street use and cost, I'd use a trac-lock.

The power lok doesn't have any windows and the carrier is 2 pieces bolted together. The track lok is a one piece carrier with a large window and spider gears.
Travis..

Power-lock has 4 spider gears, Trac-lock only 2.
The Powr-Lok is one of the most aggressive and strongest limited slips ever designed. It uses a two-piece case and six forged internal gears for added strength. The Powr-Lok uses a ramping-clutch design to become more aggressive as tire-spin increases. The composite clutches provide long life and high performance. All units are Rebuildable