It is well suited in environments that have a low change rate. Once configured, the Arista Extensible Operating System (EOS) is rock solid but changes can be a little cumbersome. The good news is that the learning curve of the Arista Extensible Operating System (EOS) commands is relative short. Many of the commands are similar to other vendors and so expertise in one command set should easily translate to Arista Extensible Operating System (EOS). Our network admins had no problem making the adjustment.
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.
Manage - Arista Extensible Operating System (EOS) is comprehensive enough that all of the commands are present to manage the device and take advantage of all of the unique features.
Scale - A single command set across multiple pieces of hardware allow us to script changes and deploy hardware easily.
Update - Arista Extensible Operating System (EOS) updates happen seamlessly and often don't require rebooting the underlying hardware thanks to it's module-by-module approach.
There are "assumptions" for lack of a better word that are baked into the Arista Extensible Operating System (EOS). While many would be considered best practice, there are others that require a great deal of workarounds for specific environments.
Some details about hardware state are hard to get inside the command structure. There aren't summarized views for many of the more routine queries.
Logging - It is difficult to output logging to a SIEM collector and also let logs remain on the device.
Many of the commands mimic or are identical to vendor commands. This makes the software incredibly easy to learn and use. My one complaint is that sometimes the details and summaries don't include a lot of details so it takes multiple commands to get all the information. Detailed output doesn't always include data included in the summary. This is relatively minor and may just be a personal preference
Cisco IOS is probably a universal standard and one that people usually use in basic network classes. Arista Extensible Operating System (EOS) is so similar to Cisco IOS that the commands to do basic configuration are nearly identical. Arista Extensible Operating System (EOS) includes a lot more detail on reporting but you do have to dig for it. Arista Extensible Operating System (EOS) also allows for much more granular configuration.
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.
No Training Budget Needed - Command set is similar to other vendors and it required no specialized training.
Reduced Downtime - Many Arista Extensible Operating System (EOS) updates can happen without rebooting the underlying hardware meaning that downtime is reduced. This makes EVERYONE happy.
Few Bugs - There are very few bugs in the Arista Extensible Operating System (EOS) production code thanks to great Q/A work by Arista.
