I'll take a Juniper over a Cisco any day, again personal preference. I really like the Juniper CLI and I am very comfortable with their platform. We looked at "SDNs", we run NSX and we just use the firewall. Problem is with complex solutions you need a team that can troubleshoot them, most people can't troubleshoot simple ethernet. So we keep things simple and old school. For example, we don't run QoS, we just invest in bigger pipes.
Arista is the hotness these days I think? When I worked in datacenter land I saw a lot of Arista for switching, some Cisco and Juni for switching. Lots of Juniper for routing, with tiny bits of Cisco for routing. One or two people had the newer Arista routers but they weren't that common. We have a few of the Arista 64 port x 100gigabit switches and some of the 48 x 25 gigabit + 6 x 100gigabit edge switches. They do pretty good so far. Pretty crazy thinking how much data they can theoretically move. - Ethan