I've been to almost all of the dog parks in the East Valley and this is definitely one of the best. I drive 5 miles each way daily to go there. It is by far the largest in Tempe (which is easy because the others are tiny). It is large enough to accommodate a lot of dogs and people (which there are at peak times), has lots of grass, 2 doggy water fountains so they don't have to drink out of community bowls, trees around the perimeter and a ramada with tables/benches, and other benches located around the perimeter. It is open early in the morning and late at night (there are lights on until 10 PM). There are also city supplied poop bags in dispensers which are usually stocked (although occasionally not, so bringing a bag doesn't hurt). The people are pretty friendly and the poop situation (people that don't clean it up) isn't that bad in comparison with many other parks, especially Cosmo and Chaparral. There is only one large section (no small or inactive section), but it seems to work out OK as the dogs aren't overly rowdy or aggressive in general. I've never seen a real fight. There is a sort of walking path around the entire perimeter and many do walk it for exercise. Overall, a well above average place to take your dog.
LOCATION: It's a little hard to find. Take Kyrene to Carver (halfway between Warner and Elliot). West on Carver about 2 blocks on the left. There are other routes, but this is the easiest, unless you're coming from west of the park.
Anyone is welcome to contact me for my opinions on the other dog parks in the East Valley.