The top of the trail is excellent quality berms with great flow. It must have received some love from Vail Bike Patrol in 2013. It swoops through aspens with a few steep sections and drops, but it's fine for advanced cross country riders.
The lower section is badly eroded and completely unsustainable. Steep rocks and roots will require most people to walk 100 yards or so. Hopefully it will get rebuilt soon.
I recommend riding the top section but skipping the bottom (it's obvious and easy to avoid - just keep going down the dirt road instead of turning down the eroded rock field).