I used AICP to extend the life of an LG G2 and was very happy with it. Many may not realize that the builds for each phone can require significant tweaking off the base ASOP builds and much of that is dependent upon vendor documentation and lockdown. That is a lot of work for a small community of devs deadicated to these types of projects. Then consider how many Android phones are out there (Samsung alone has 388 per GSM Arena)
AICP really let me down only once: I'm semi-religiously doing the weekly security updates. Once that broke the installation, because it was a major version upgrade (I think Oreo to Nougat). I suppose I should have wiped and installed it manually, but the AICP update center just enqueued it like a regular security update.