Modechoverb is my goto algorithm as I can get that algo to sound like my old quadraverb. Next inline is the plate reverb. But I play ambient verve like sounds. If you're just doing covers though, then I can't really see a reason to buy anymore algo's than what it comes with. You've got most bases covered right there. If you want to play around and have some fun though then black hole or modechoverb are great
