Pros:
Simply put, Highland Hills is epic. It's the most monstrous, mountainous course I've ever played. I love courses with elevation, but this actually takes it to an extreme. Don't get me wrong, there are tons of fun, unique holes. But the hills are soooooo steep that simply walking the course is hazardous. Some holes are downright dangerous. You've heard of death putts. "H!H!" (as they like to abbreviate it), has lots of death putts, death drives, and death approach shots. To sum up before I list my pros and cons, Highland Hills is fun + extremely strenuous + downright dangerous. In other words, epic.
PROS
1. Stupid crazy elevation.
2. Really beautiful course and surroundings.
3. Very challenging.
4. If you like extreme hiking / mountain climbing, you'll love this course.
5. One of the most unique courses you'll ever play.
Cons:
1. This course is dangerous. It's way too steep for solid footing on upshots...and even walking from hole to hole. I played in the fall after days of rain. Slick leaves + mud everywhere + mountain goat paths = twisted ankles and busted asses.
2. Huge disc loss risk on this course, from blind tee shots to autumn leaves to discs rolling down hills for MILES to thorns to creeks to a river! (Did I mention this course is epic?)
Those are really my only issues with the course (but pretty big issues).
Other Thoughts:
If someone asks you to join them at H!H! for a round, first, ask yourself if they're planning to do away with you in the woods and dump your body in the river. Then get your heart checked and put on your hiking boots. Seriously, this course is not for everybody and be careful.