Pros:
This course plays and feels like a John Houck, Austin-area course... and that's a good thing. mostly flat with a few gentle elevation changes in the meadow, this could be a piece of Texas, and the hills of trees surrounding the course could be central Texas hill country -- a very pleasant setting for a course. When I say the course feels like a John Houck design, I mean that in a very positive way. The holes make very good use of the available land and are designed in such a way that most of them will force score separation between good and bad throws. The signature hole -- for me -- is not hole 18 that other reviewers have mentioned, but rather hole 2, a ~600' hole across rolling hills with OB on the right that requires a low-ceiling shot or roller under a canopy of large trees followed by a precise upshot to a basket protected by loose trees in front and a huge evergreen tree in back that will turn over-long approach shots into very difficult birdie-three putts from inside the pine needles.
I hope the park eventually implements a system to show which pin the basket is in -- that would speed up rounds immensely, saving you from having to search out the basket placement.
The one time I played the course, the fairways were well mowed and the grass on the meadow holes was very conducive to roller shots. Debris/trash/fallen branches, etc... were very minimal.
Overall, not a super challenging course -- even with mostly long baskets -- but well designed, and with enough variety, that you shouldn't get board playing several consecutive rounds. Great place to practice roller shots as well.
Cons:
Biggest cons here are that the unmowed areas -- the rough -- can be really hard to find discs in. And they underbrush is a highly likely place for ticks. When we were there, the meadows were being used by a small herd of deer, so we made sure to wear Permetherin-treated pants/socks and plenty of DEET to help keep the deer ticks at bay in the overgrown areas. We didn't experience any problems, but we were well prepared -- I'd advise others to take similar precautions here when walking through the tall grass in the meadow.
The other con -- mentioned by others -- is the lack of a system to show which basket placement is in use. Other nearby courses -- like Tyler -- have a great system with a little rotating dial that indicates the basket as being in A, B, or C. This simple fix would aid the course playability immensely.
Another con (in my book) is completely subjective, so I'm not using it to dock points form the score, but I mention it solely for others like me: this course has very, very little elevation. I love elevation shots, and so many other PA courses have great elevation changes that it is a little disappointing to come to Tinicum and be on mostly flat ground. It is still very fun to play, but lacks the thrill and awe that would come from having a few great elevation holes. When I first got to the course and saw the tall, tree-covered hills behind the park, I had hopes that one of them would come into play, but alas -- no luck there. Again, I'm not docking the score, but just mentioning this for other elevation junkies like myself.
Other Thoughts:
My favorite feature of the course -- it is rare to get to camp right on a disc golf course, and Tinicum makes that possible. On a recent disc golf roadtrip, we camped one night at Tinicum. Camping is pretty decent - just call the parks department on Monday or Tuesday and they'll reserve a campsite for you. Ground is flat and root-free, and you wake up right next to the course. It's great to wake up, grab your bag and start a round. So props to Tinicum for camping convenience - though make sure to call the parks in advance, because it is hard to track down a ranger at 9:30 p.m. to explain you want a campsite (which is what we had to do). Much, much easier if you plan ahead and reserve a site in advance.
For us (a Thursday night) camping was $15 and the campsite was in a great location with firewood, clean picnic tables, good fire pits, a very basic bathroom (no lights or showers), and no one else around. Great place to camp, and the ranger was very helpful when he came by around ~10:30 to check us in.
To me, the camping convenience is one of the best features of this course -- especially if you are doing a trip and visiting several PA courses. Camp here, then head up the road to Nockamixon, Lehigh Parkway, Jordan Creek, Tyler, etc...