The free or very cheap VST you trust and use ?

^ What didn't you like about it?

EDIT: Btw, I just noticed that the paid version of the plugin is still just the Hall algorithm... I always figured that I just had a limited version because it was a free. In that case, I would say that you are better off checking out the competition for the money. Check out the Valhalla plugin demos for example.
 
I've never bought any commercial reverbs so my statement lacks a lot of credit but I really like the classic verb. It's free, has plenty of parameters and sounds good to me. I also like the DVS Reverb which is also free. It's very simple and i like it to add some room to guitars.