Pros:
This is one of the most beautiful courses I have played. Helsinki is great in the summer. It was in the mid 60's and light until 10:00P. The locals are very friendly and most speak enough English to help out when you get lost.
Cons:
It looks like the area has been used for picnics and partying for a long time. There are way too many cans and butts.
This is a very physically demanding course. It is basically a hike in the mountains. You don't need ropes and pitons, but it isn't like any course I have seen. Be ready to spend the day scampering up and down rock outcroppings like a mountain goat.
Other Thoughts:
The first challenge of this course is finding it. If you are coming from central Helsinki, take the 4T tram to the Meilahden Sairaala tram station. The station is on Tukholmankatu Street in front of the Meilahti hospital campus. Walk west on Tukholmankatu until it turns then walk SW across the street and parking lot and take the path south to the Meilahden Liikuntapuisto, a Tennis and sports club. If you look on Google map, the area to the southwest between the gym (identified as "Unisport") and the sea is a mix of exposed granite bedrock, small cliffs, dense woods, and footpaths. This is the golf course.
The whole area is crisscrossed with foot paths for jogging and smaller paths beaten down by people looking for the Tee pads and their discs. There are no fairways. There is a Tee pad, then a bunch of forest and rock, then a basket. Finding the next Tee is also difficult but most have a helper sign painted on the ground near the previous pin. I never did find #1 after 20 minutes of searching, so I started at #2.
Most of the holes are short. I don't know if a map exists, but I would guess 180' - 240'. Two were maybe 280'. Most of the Tee pads are a relatively level spot on the granite with a painted line. Sometimes it is just a fallen tree (see pictures). In all but a few cases you cannot see the Pin and must hike the hole to the end to plan your drive. Unfortunately, this also means that you can throw up into other players that you didn't know were ahead of you. (I understand that "Se on alle kori" means "It is under the basket".)
The course is characterized by extreme elevation changes, dense woods, and blind shots. It is safest just to aim for some exposed rock and try for a par. Birdies are possible, but risky. I was lucky to leave with all my discs. The forest is very thick. There are tons of wild blueberries, so at least you probably will not starve to death finding your drive.
If you suspend your preconceptions about what a disc course should look like, then you will have a great time. It is a beautiful hike in the woods with your discs.