Pros:
This might be the most manicured course I have ever played. The front 9 winds around shallow man-made ponds, waterfalls, wood bridges, walking paths, a variety of trimmed trees, and sweeping areas of wild grass. It's pretty scenic.
The back 9 (added in the spring of 2012) is longer - between 275 and 400 feet on most holes - and plays through fairways mowed out of wild grass. A few of the holes are wide open, but most have some trees to force different lines.
There are three configurations to the course: red, blue, and green. From what I could tell, none of the configurations was all easy or hard positions, which I like. The bases of the baskets are colored accordingly.
The tee signs are okay, listing the distances to the various positions, although there is no indication of where the basket is (this was only an issue on #1). Every hole has a pretty good concrete tee pad. They aren't terribly long, but you won't need a full run-up on these holes.
I love that water is brought into play on multiple holes on the front 9, but you could wade in and get your disk if you had a bad throw (it's no more than 1-2 feet deep).
Navigation is pretty simple after you get past the first hole, and you won't need a map. Just know that the tee pad for 9 starts near the parking lot.
There is some elevation. Most of the holes play flat or slightly downhill, but #9 is all uphill.
Cons:
From the first tee pad I could not see the hole and had to walk around the greenhouse to see where I was throwing. The first hole required a long turnover shot for RHBH players (that's a good thing), but it was a blind throw that could be unsafe if there are people on the other side of the greenhouse.
The front 9 is very friendly to children and rec players, and most of the holes aren't too technical, so advanced players may be a little underwhelmed. But none of the holes is wide open, either. The back 9 will offer more of the challenge advanced players are used to.
There is some risk of lost discs on a couple of the holes on the back 9 due to the high grass off the fairways, so spot well.
There is a $5 park entrance fee. You can see how the money goes into the course, though.
Other Thoughts:
Mahoney is a state park that gets visitors coming for a very wide range of activities. I saw a family playing disc golf while I played, and it appeared they had never played before. This is a good thing. Get people who are at the park for other reasons to try out something new, and maybe they get into it and start looking for courses in their hometown. The course is clearly aimed at recreational players, but it is not a cakewalk by any means. I did have several bogeys. I also aced #2 on a thumber that somehow stuck in the chains!
I hope this course succeeds, because this park has a TON of land that could make for some a whole disc golf complex. And it exemplifies the kind of Nebraska beauty that most people are unaware of: rolling hills with a variety of wildgrass, any tree you can think of, and creeks and rivers carving out new valleys. It makes for some nice disc golf.