Pros
Arista has a good work-life balance with flexible hours and they just started matching 401k contributions. The products are more reliable than their competitors' are, and Arista employs a comprehensive automatic unit-testing system that is unlike anything the competition has.
Cons
During interviews, Arista proudly touts that every employee is afforded time to do interesting work with teams employing rotating job schedules in which every employee takes turns at the interesting aspects of software engineering and the not-so-interesting aspects of software engineering. What actually happens is that team managers come up with multiple ways to describe bug-fixing and rotate the same 2-3 employees through different "projects" that are all the same maintenance work. If you're not one of these 2-3 employees you might enjoy working on interesting projects and learning new things. At Arista bonuses and raises are determined by the "A-review/peer-bonus" system, in which every employee rates their colleagues based on their perceived contributions to the company. Naturally this tends to favor the same employees who are getting the interesting projects since nobody cares about fixing bugs. If you don't get a good a-review, then you aren't getting any bonuses or raises that year. So you can waste your life away by working hard and cleaning up other peoples' bugs, and *maybe* after a couple years you *might* get slotted into a project visible enough that your coworkers *might* notice what you're doing and you *might* get a peer-bonus or something. Alternatively you can fill out a job application at one of Arista's many competitors and get a much larger pay-hike now.