Very nice place, all panda areas are large open spaces with many different points of view for tourists. Definitely the place with the best animal treatment I've seen in China. Lots of information in English available. I would highly recommend going with a tour guide, this allows you to go directly for the best sights at the best time. Guides knows precisely which pandas are being fed at which time. And for most of them, that's the only time of the day when they're active.
If you can spare some money for a guide there, don't think twice, do it and book a tour in Chengdu.