Maybe, maybe not. Context is important. While the number of users is certainly important their activity is critical to make that determination. For example, If these guys are developers they can generate an enourmous amount of IO. In fact, I was given a 300 users requirement for north of 7GB/s not too long ago. Yes, that is Gigabytes. So we need some more detail.
The number of users is important, but just as important is the amount of IOPs required for each user. Has that sizing been done?
Once the IOP requirements are set, acceptable latency levels need to be established. Depending on the FAS model deemed most fitting for the workload, VST Flash (FlashCache or FlashPool) may suffice. But we can't really give a good answer until the sizing has been done. If you need help with that, let us know!