Pros:
It's a very technical course that feels longer than it is because of the terrain and trees and it's in a part of the St.Louis area where there are currently no other courses to play. The tight spaces and all the skinny trees really make even an experienced player stop and think about their line, disc and approach strategy. The course gives you an opportunity for variety in both your throw style and discs used.
There are trash cans at every tee and the park is really clean.
There are really excellent score cards/maps in the box at tee-pad 1 at all times.
Although the holes at this course are mostly short by contrast to parks like Creve Coeur and Sioux Passage, there are a few that you can actually let it rip a bit on... but it has to be a very accurate rip; just a few feet off in either direction and you're going to nail a tree and turn that big drive into a big mistake. Even holes, like 2, with an easily reachable distance require a perfect line (and a little luck) to reach the bucket through the trees.
Holes 2,5 and 7 offer a cool (and narrow) dual path to the pin scenario so that you can choose your backhand or forehand, hyzer or anhyzer throw, in an attempt to trace the best safe path to the basket.
I like that each of the baskets are bright and easy to see and have the hole number as well as the Par clearly labeled right on them to see from any direction.
Another great thing about this course is that it is ALL in the nice, shady woods; that's a BIG and welcome benefit in the summer heat.
Cons:
It has some tee navigation problems for 1st time visitors who don't grab a map/scorecard: it's easy to get mixed up at the bridge that runs between tee 3 and 5. then it's a little walk down the path, over a different bridge and past the pond to 4. Hole 5 is right up the hill from 4's basket on the opposite end of the bridge you tee off 3 from and then hole 6 is at the top of the wood and stone staircase just past basket 5. Then there's 7... hmm, 7... has anyone seen 7? Well, 7 is back north into the park, across the path between the lake and the playground and NOPE, that's 9, keep walking and look to the left. "Oh, there's 7." Then you walk up the stairs and past the flower garden to find... tee 8. Now, you can march back down the slope to the left, taking you across the middle of the 9 fairway to find tee 9 and throw a really awkward, non-disc-golf-like shot back up the hill and you're done. Other issues are the worn-down dirt and terrible gravel tee's built by some Eagle Scouts. Some occasional marshiness on the south side of the fairway on 7 and a general lack of maintenance.
What really stinks about this course is the parks dept treating it like the unwanted stepchild - it get's no respect and no love... seems like it is intentionally neglected and set up to cater to as few players as possible.
UPDATE: A couple of baskets have been damaged (bent and beat out of shape and they stand crooked) over the course of 2014 and the parks dept. has done nothing about it (and the club has been told that our assistance is not needed).
Other Thoughts:
When it's been raining in St. Louis (despite what it seems would be the case with a mostly dirt course) Watson Trails dries quick and can generally be played the day after a storm. Another unexpected thing on this all-woods course is that it's easy to find your disc (except for really bad throws on 7...) because there isn't much underbrush.
UPDATE: All the maintenance on the course/park has done nothing to improve the course, except cleaning up the disaster of honeysuckle and weeds on the left side of 7's fairway. Hole 9's tee was moved to a terrible position that doesn't make any sense at all - discs just don't fly that way folks. The parks dept's efforts at controlling runoff and erosion were poorly planned and executed - the problem is just as bad as before and left some boggy areas to deal with. Vandalism and graffiti continue to be a problem at a park in the middle of a "wealthy" neighborhood and right next door to the police station - WTF? Also, some really dumb tee posts, which look at home on a run down mini-golf course were put in last year and half of them are right where you're going to hit them with your hand when you throw - watch out.
IMPORTANT NOTES: All the tee signs are WRONG. All holes are par 3 except hole 1 is par 4... and the distances are off because this course has been rearranged several times to make room for other parks projects.