This place is really awesome. It's one of those places that you don't expect to exists in the middle of a city. I've taken my kids twice now and both times have seen flocks of unique birds. Yes the park is not as "maintained" as a regular park and has some fairly overgrown areas but I think that's what brings in some of the more exotic birds. There are also plenty of paths and breaks in the brush in which you can walk through the overgrowth and get right down to the water and get very close to the birds without upsetting them.
I've only taken a 200mm and 210mm lens with me and got some really up close bird shots. It's really hard to carry my heavy 500mm and take the kids so I haven't tken it yet and haven't felt like I'm missing much. There is a more manicured area/lake where you can get some good shots of ducks and coots that walk up to you/expecting to be fed. You can also fish in this lake and it's stocked with trout and bass. Some of the more overgrown parts of the park and ponds you can see lots of shorebirds, egrets, multiple species of herons and geese. I plan on going every couple of weeks with my kids in the hopes of seeing some chicks soon! It's close enough to my house in Gilbert and inexpensive enough (read: FREE) to show up once a week just to check.