Fantastic park for dogs and people alike!
I love the art! People have created pretty huge sculptures using only found junk (metal and rubber, etc.). There is a samurai, a Poseidon like figure, and many more. Lots of great graffiti and smaller pieces of art. Also, one of the best views of the Bay i have ever seen. If you find yourself wondering whey there is so much junk and concrete there, remember that it used to be a dumping site for the SF earthquake debris.
There is also a tiny beach right before the main park area (which has only boulder beaches) that is perfect for your water loving dogs and kids.
The only problem is the homeless. They have kind of set up camp there. They live in makeshift homes kind of like permanent campers. In the times I have been there they haven't bothered me or anyone I saw. They aren't in the way of anything worth seeing so it really shouldn't be a concern, but it is a little sketchy. A night trip by yourself or with a friend wouldn't be recommended.
Oh yeah, it's free!