I've done White Rock Loop a few times - once counterclockwise and twice clockwise. It is definitely easier to do clockwise. There are a couple of possible trailheads. You can either start from White Rock Trailhead or Willow Spring Trailhead. We've always started from the former. The reason I think it's easier to go clockwise is because you start downhill and end downhill (at least from White Rock Trailhead). Most of the uphill part occurs behind the mountain. For some reason, it doesn't feel as bad going in that direction.
I like the fact that this hike is a loop. Most of the hikes in the area are out-and-backs. It's nice to not have to retrace your steps and see the same scenery twice. Speaking of scenery, this hike has a diverse offering. In front of White Rock Mountain, it's the typical Mojave Desert. But once you step behind that mountain, it's like you've left Southern Nevada altogether. Stop often to just take in that beautiful view.
The loop is about 6 miles long and probably takes an average of about 3 hours to complete. It has a well-defined trail for its entirety. I'd rate it a moderate and worthwhile hike.