I am the local Southern California Field SE. You are probably familiar with Rich Cincinelli since he was the SE in your territory before he retired. Good friend of mine going back maybe 25 years.
Anyway, as Paul mentioned we have no plans to EoL the S-Series. In-fact the S-Series is central to our solutions like NAC and Analytics. These solutions rely on the unique abilities of the Core-Flow ASIC employed by the S-Series, to provide visibility and control.
Cal Optima is a large customer in Orange County that just completed their core upgrade using S-Series. They are the county run insurance provider for low income tasked with administrating Medi-Cal or California's version of Medicaid. Their last core architecture was in place for 10 or 12 years and was Gig based. This upgrade brought 10 Gig to nearly all uplinks and resources. Obviously these guys are extremely conservative.
Feel free to contact me directly with any questions.