The best related posts plugin we have tested

This FREE plugin does what it claims and has just about any feature we wanted in a stand alone related posts plugin. Two things worth mentioning:
1. The related posts are really related to the title and content of the post – critical for SEO
2. A complete set of features to tweak important aspects – the list, size, no-follow etc.
3. SPEED – we have over 100k posts and custom posts that this plugin zips through. (Caching feature makes it almost invisible.)

A brief support interaction leads me to believe that they back up their product with prompt and attentive support.

Thanks for a great plugin!