Re: "A ground-up-designed operating system underlies this."
Disclosure: I work for NexGen Storage.
There are both pros and cons of using something like ZFS. Pros include things like speed to market, comprehensive feature set, and decades of development and refinement. Cons include things like decades of development and refinement, detailed expertise and knowledge of data path, challenges around differentiation.
NexGen decided not to use an existing file system because the software design paradigm of the last few decades has revolved around disk drives and managing capacity. NexGen believes there is a big gap in the storage market around providing customers with the ability to squeeze every ounce of performance out of flash (and other emerging medias) and the ability to manage performance just as effectively as managing capacity to deliver predictable application performance in a shared environment. The easiest way to solve these problems are to start from scratch and design a new architecture and data path to avoid being burdened with legacy software designed for disk. It's taken us a lot more work from an engineering perspective and has taken us longer to get to market but we believe our approach will pay dividends in the long term. Thanks for your interest and question.