No Crowds, Great for beginners, Everything groomed
Small, slow lifts
The reason this place is great for beginners is that they can ski the entire mountain. No one is going to run them over, because crowds are nonexistent, they probably will never wait on a lift all day, and the mountain is so gentle that they can ski green, blue, and black (they're all easy). So, it follows that experts will be very bored here. There is nothing marked double black, and frankly, nothing here would even be black at any other resort in the area (it would almost all be green).
Ski Cooper does have a bounty of snow, and you can definitely find untouched powder even days after a storm, because there just aren't enough bodies on the mountain to ski it off. Also, they groom almost everything, so if you like making big, fun turns on perfect snow, you will really enjoy a day here. The runs are short and the lifts are slow (8 minute ride on the backside triple, 14 minute ride on the frontside double), but the lack of crowd and quality of snow really does make up for it for one day.
You will easily ski everything in a day, so you don't really need suggestions for which runs to check out, but here are the ones that stand out to me:
Nightmare (perfect pitch for fast GS turns)
Tenderfoot (smooth and fun through the trees)
Pando (really fun route directly underneath the double chair, bumped up in the middle so you can go back and forth catching a little air each time)
Trail's End (longest run and secluded in the trees)