Fantastic opportunity to make a huge difference, both in the industry and personally
Pros
Industry: Storage is huge and in dire need of improvements. Pure Storage is arguably THE leader in bringing flash memory to the storage industry. The technology is already making a difference in the industry. Product is disruptively fast, easy to use, & cost effective. Marketing is innovative (check out Love Your Storage guarantee & Forever Flash programs... they're simple but unimaginable from the others). Company: Has a great product. Growing fast. Has a great team (board, management, technical leadership, engineering/sales/operations staff). Innovation isn't only technical, customer satisfaction isn't just marketing. Values: Tries hard to be strategically smart. Creativity is recognized and appreciated. Fun is recognized as a good thing. Personal growth is desired and allowances are made. Personal: You can make a difference. Lots of opportunities to learn and grow. I'm sounding like an ad for the company, but I'd still be there if it weren't for personal issues.
Cons
It's still a startup. Lots of infrastructure needs work. Growing fast has challenges. The folks you worked with on the last project are unlikely to be the same for the next project. You're going to have to train people. Projects are dynamically adjusted in priority, features, staffing levels. This requires some mental flexibility and a focus on doing what's necessary vs cool.