Yes, though I'd say it was a commercial product built on the Eclipse platform because in addition to the extra plugins there are the "features" they're bundled into, the install program documentation, and other accompanying material and support.
I had used Eclipse for about a year, and then took a job with a company that used WSAD 5. I was pleasantly surprised to find that WSAD is basically 'Eclipse on steroids'.
Don't get me started about those stupid light bulbs.
