Pros:
It's one of the only courses inside the D.C. Beltway and is pretty accessible from the Beltway, the G.W. Parkway or Hwy. 66, but it's location is the most positive aspect of this course. Shady, so that's a bit of a plus, too, I suppose.
Cons:
This course is poorly laid out. All nine holes are short (longest is less than 300). The long tees are very hard to find -- now, with some work at the park, they are gone -- you have to guess or make up your own. The rough is nasty, nasty, nasty thorns and overgrowth, and it is obvious the park is very seldom played by anyone, and even more seldom tended. The overgrowth causes some of the holes to be blind shots, even though the holes are only 200'. Small stream runs through and the area can be both swampy and filled with mosquitos. Poison Ivy and Posion Oak add to the hazards of the rough.
Teeboxes are roughly 4'-square with boards on every side and uneven dirt as the tee surface. It pretty much forces stand-and-deliver, since any run-up is dangerous. Fortunately, since the holes are so short, stand-and-deliver is not going to hurt you.
Other Thoughts:
I've been out there at least five times now, and usually regret going. I'm a pretty decent player and don't often loose a disc, but I've had at least one out there that wasn't worth looking for because of the overgrowth. If you are going to try the course, bring discs you don't care about in bright colors that will stand out against the thick greenery. Use bug spray. Wear pants. It's that kind of course.
Note (08/08/08): Played McLean again last night with a friend. We did a putter-only challenge: two rounds each from both the short and long teeboxes. The course plays much better with only putters or superclass discs (I've played there with a Zephyr). The thorns are as thick and nasty as anywhere I've ever seen, and very, very close to many of the baskets. The upside of using putters are that you can reach 8 out of the nine holes with just putters, and they aren't nearly as likely as drivers to dive hard and bury themselves into the thorns. We actually had an enjoyable round. But I would highly recommend using putters or superclass discs if you are going to play.
The other +/- I should mention is the single-chain Mach-1 baskets, which bounce (or fail to stop) a lot of putts that would stay in almost anywhere else. So putting is a challenge, but not a challenge that will necessarily make you better for other courses, so it forces you to change your putting style without offering you anything in return. The baskets favor a very gentle loft putt; people who throw other styles of putts will get spit-outs at least 50 percent of the time.
[05/2009 update] If you're looking for the long tees, they have completely eroded. Just make up your own long tees, usually 20-70' behind the regular tee and a little off to the side. Makes for some slightly different lines.
After the replay, my best advice if you decide to play there remains this: wear close-toed shoes and long pants.
The park only gets it's 1.0 star because it is mowed, and -- by and large -- it is an area seldom used by dog-walkers, joggers or other folks. A course has to pose physical-danger to other people or be completely covered in nasty trash like hypodermic needles before it could drop much below a 1.0, IMHO.
There are a few non-disc-golfers on the course, usually walking through on/near holes 1 and 9, but most of the course is clear. Double-chain baskets would bump this course up at least .5 stars... but really, I'd rather see a total redesign or a removal of this park. No one who plays here will have any idea what disc golf is really supposed to play like, and no pros will spend their time here, since not even the baskets are helpful for realistic putting practice, since they don't translate well to other courses.
The course is mowed -- or seems to be -- even if none of the underbrush is tended. With a lot of work, this course could probably be brought up to be worthy of a 2-star rating, but that would require a lot of work that could be put to much better use elsewhere.