I've been using filter with Amethyst for about a month now, and I think it's fantastic! I use it as a general relay, and a search relay.

It's the foundation of my general relay config. I start with filter, then I add other relays (that filter isn't already aggregating) that provide specific content I want in my feed. It's very fast as well. My feed loads immediately on startup instead of taking 30 seconds to fetch from all those relays.

This method has greatly improved my relay efficiency, and eliminated the need to have 20 general relays configured. Instead, I've got just 6!