I've been doing Linux administration and cybersecurity for more than twenty years. I found moving from Fail2Ban to CrowdSec came with a fairly steep learning curve, in my opinion. It lacks a lot of common plugin modules and writing your own requires a lot of moving parts and a new quirky language. For example, OpenVPN is an extraordinarily popular software yet no pre built collection, configuration or bouncer exists for it. I found it was not particularly easy/quick to implement a CrowdSec policy for guarding my OpenVPN ports, unlike with Fail2Ban which can whip up a rule quite quickly and with less files. I dont think the CrowdSec technical documentation is particularly well fleshed out nor easy to follow in comparison with other open source projects across the space.

Easy to install and maintain. Easy to extend scenarios and blocking behavior. "Free" blocks with global blocklist based on everyone's reports.

It's free and given I have two start ups in pre-seed round that is a god send. It is fantastic software that I use on all my servers. From basic ssh bouncers to more complex strategies.