said by HiVolt:What do those do? newer version of the ERX's? or different functionality alltogether?
From the looks of Juniper's datasheets, the SRX appear to be corporate-grade firewalls (2-15Gbps), AV firewalling (350Mbps), IPSec firewall (1Gbps), VPN gateway (1.5Gbps), etc.
Looks like these will be used to protect the office against intrusions, malware, DoS and other stuff. Not as part of their core routing infrastructure - much too slow for core network applications.