An internet search can provide you with names of all the top playground companies, and every company can provide you with references. But, what you want to do is consider each product, what are the things that make it different from the other products, and do those differences fit your needs better.
I guess I should say, up-front, that I am the Director of Marketing for Safeplay Systems, but I'll try to keep my response generic. (Our product line is EcoPlay Playgrounds.)
I wrote an article for RELIGIOUS PRODUCT NEWS magazine, that discusses how to choose a playground vendor. The link to that article is:
www.religiousproductnews.com/articles/20...ground-Equipment.htm
There are many factors to consider, and the relevant factors differ for each purchaser. For example, another person that responded here mentioned they were located on the coast, and purchasing a playground made from recycled plastic was VERY relevant to them. If you live in California, PVC-FREE may be the most relevant item on your list. (Actually, Phthalate-Free is what is important.) Or maybe your funding process will require a playground designed to be installed in multiple phases, over a period of years. Each situation is unique.
I hope the article helps as a guide for your playground equipment vendor search.