Pros:
Benson State Park is more like a rest area on the side of the road than a State Park, there is access to it only going east on I-84 and it's only a small parking lot, bathrooms, some benches and a very short disc golf course. This is the type of place you stop at while on a family vacation and everyone needs a rest from sitting in the car so you go have a picnic and play some disc golf. Aside from all of that you have wonderful scenery in the beautiful mountains in the background and the Multnomah Waterfalls.
The best holes on the course - Holes one, two and eight were pretty fun and almost worth the $5 to park and play. Hole one is a very low ceiling shot with lots of tree and bush obstacles to the longest basket on the course, right at about 300 feet, definitely the hardest hole on the course, very challenging. Hole two is a short (100 feet) tunnel shot over a running creek, this is a prime opportunity for an ace but if you hit one of the bushes on the left or the right you could end up in the creek. Hole eight is longer shot over the creek but going back the other way and is a hard line to hit and this hole is a difficult hole if you don't hit that line. You don't have to worry about losing a disc in this running creek as there is enough debris to block it and there are plenty of long sticks around to fish it out pretty easily.
Cons:
The biggest problem that I find with the course is the very short holes lengths that will make this place boring for just about anyone but people brand new to disc golf. The baskets are a bit of an eyesore with the chipping paint and rust, it would be nice to see some work to make them look good again, though there is nothing wrong with their ability to catch discs. It is a pain in the butt to try and get to if you're coming from westbound I-84 as there is no access.
Other Thoughts:
This is the perfect place for your first ace, while we were there, both of us hit basket and were really close to getting an ace. If you take the right attitude and a catch frisbee here you can make it fun.