Webhosting security php-fpm or jail

Hi guys,

I have a small server that I use to do web hosting..
At the moment, I isolate every domain in a jail.. So at the moment I have about 20 webjail all running teir own webserver and php version..

My question is this:
From a security point of view is creating 1 jail per domain better than creating php-fpm account isolation via php-fpm pool and sftp restricted to home directory?

I have a lot of overhead in jail maintenance at the moment and I was wondering If I was overkilling the spec of my structure