Reply to Mixed in Key vs. Rapid Evolution?

Has anyone had any experience with mixed in key or rapid evolution? I know RE is free and Mixed in Key is like 50 bucks. I would normally go with the paid version of things when I can because you get better support most of the time however all i need this for is to tag the keys of the songs so... Does Mixed in key offer any significant benefit over RE and if not is RE stable enough to use and rely on when djing professionally? I am using SSL and will be using Serato DJ soon as i just purchased a 64.