[kopirgan]

There's several AOSP based ROMs in forums like xda. Mostly developed by enthusiasts.

Recall using one years ago on my Samsung device with happy results. That was long before banking apps etc. Wondering what's the difference with this? Extra security?

[tranq_cassowary]

This is a production grade OS, it's made by professionals, it's not hobbyist. It keeps up with updates of upstream Android and Linux kernel. It has a ton of good security and privacy features.