Expensive, proprietary, has a bunch of very specific stuff that is made incompatible with everything else on purpose, their software is kinda trashy, and it's honestly not even that good for general setups. They still dominate in more niche setups, and in some cases are unavoidable, but if I can use an alternative, I'll try.

Also cisco certifications are another sketchy branch of their business. They realized they could milk their ubiquitousness in the market to get even more money with certifications, and they went all in. Some of those make some kinda sense (even tho they're touted as general networking certifications when, due to the aforementioned purposeful incompatibilities, you'll only learn how to work with cisco and nothing else). Some, however, are outright bs. They have certifications for english. Cisco, certifying english level. And it's still an expensive certification, more expensive than some actually official certifications.

Expensive and proprietary.