We visited it last week while in town purchasing a lot in the village of St. Charles. Woo Hoo!!!
It is definitely a small dog park which is run by members who join for a $40 a year fee. The hours are either 7am-noon or 8am-noon. Short, but if you plan that time slot into your schedule it would be doable.
There are two sections to separate the large and small dogs. Members pick up after their own dogs (clean-up bags are provided and included in the annual fee).
There is a covered area for members which provide shelter from the rain and sun as well as several shade trees in the park. People were sitting in chairs, I'm not sure if they are there permanently or if people bring their own.
As far as cleanliness, it seemed very clean while we were there.
We are still not sure which park we will join, but it is nice that there are options.