Block stops them from seeing your reviews, plans, profile, and following you. They can't read or react to anything you publish. They don't get told they're blocked, but they can usually figure it out.

Mute is one-way. They don't see anything different — to them, you still appear to follow them and read their stuff. You just stop seeing their content in your feeds. Use mute when you don't want to make it weird; use block when you actually want distance.