Well suited for building management networks across the organization as it has been reliable without much downtime. Since it has great switching qualities, it suites well for data center and end-user connectivity using access switches. It might not be the best for routing, as other XOR software has proven to be superior for routing.
Juniper Operating systems are well suited for distribution and edge networks. When we evaluated them for a proposal to core networks we decided to go with other vendors, as the processing capacity of core routers was lower. Typical environments Junos OS has fit in our organization are enterprise, customer edge, distribution networks.
By this point, there are several "flavors" of the Cisco IOS such as XE, XR, and the standard Cisco IOS. While they are all fairly similar, there does exist syntax differences between them. It would be ideal if at some point in the future, Cisco is able to unify all of them into one standard operating system which would use the same syntax across all platforms.
While overall Cisco does a great job of QA'ing their IOS, no matter the release, there's always some minor bugs. I think it's important that Cisco continue to pour resources into their QA team to test their software.
While I'm very familiar with the graphical readouts of "show processes cpu history" I would love for Cisco to eventually find a more intuitive way to display this data. I can't begin to count how many times I've had to teach more entry level (and even mid level) engineers how this graph is interpreted.
I do wish that Cisco had something similar to Juniper's "commit check" or "commit confirmed". This helps validate the changes you're about to apply, and catch errors, so that you have a better idea of the impact of the change.
The data that Cisco IOS is able to provide is extremely relevant, it's fast, and it's intuitive. I also love that you're able to leverage things like macros or EEM scrips to run multiple commands at once. This is especially useful when you have more junior or entry level engineers in your environment and you want to provide them with a "shortcut" by having them type a single command to execute multiple commands.
Cisco IOS is the most stable I've used, has the best TAC support, has the best knowledge base articles and white papers from Cisco, is the most intuitive, is one of the fastest, and since it's the most widely used network appliance OS, chances are that most network engineers you encounter will have the most familiarity with Cisco IOS than with any other vendor's OS.
We have stuck to iOS for datacenter networks for many years due to familiarity and ease of use. Junos OS is well suited for business customers, due to cost-effectiveness and not frequent changes to end routers. Junos OS is very comparable to its competitors, but it bit behind on core layer solutions.
Cisco IOS has had a positive impact in how quickly we're able to mitigate issues and outages due to how fast it's able to display the exact data we're looking for and because how the relevant that data is.
Having a stable operating system means less network issues and less outages. It goes without saying how valuable this has been for our organization.
Fantastic TAC support from Cisco! In the rare instances that we're faced with a very complex issue, or unfamiliar territory, Cisco TAC has historically done a phenomenal job of assisting us and getting us sorted!
