Pros:
First few holes have some interesting challenge. The woods are heavy so you have to deal with obstacles, but they aren't so bad that they prevent good shots. Discs can get lost in undergrowth though.
Cons:
The site does not appear to be maintained at all. This was probably the fifth course in the PDX/Salem area I went to this year, and all those courses have had some kind of maintenance done on them. However, when we got to hole five the grass was over five feet tall and we could not even see the basket. We wouldn't even play the hole for fear of not being able to find the disc. For hole six we could not find the teepad and checked two different online maps to make sure we were in the right spot. For holes 7-9, the tees were in a nice open field for some easy beginner shots, but again the grass was probably 2 feet tall. We could only spot the tees due to the missing patches of grass and again we didn't dare throw discs for fear of losing them. At this point we just gave up because half the course was unplayable. You could say that I just went at a bad time, but again other courses in the area are playable and another review from somebody who went a month after I did also notes that two holes were unplayable due to overgrowth. So this would seem to indicate a persistent problem.
Other Thoughts:
Having at least walked the course, I can see where this course could get a rating of 3 or 3.5 if it were playable. I suppose if you live in Canby and this is all you have nearby its better than nothing, but if you're just passing through, Wilsonville and Champoeg are only a small detour away.
Not related to the actual course, but the walking paths through Eco Park itself are incredibly beautiful. As other have noted, there is a half mile walk from the parking lot to the course, but its worth making a detour to right a bit and going through the wooded path instead of the jogging path.