After seeing this thread, I went and inspected my spade connections on the speakers and amps. My amps are McIntosh and they provide a handy wrench. None of my terminals were loose after two years. McIntosh uses very good terminals and I have very good spades on my speaker cables from Morrow.
Bananas rule, spades drool. End of discussion.
I just checked my speaker connections. All using bananas, all nice and tight.
The number of times I’ve had spades get loose instead though.....
Point is, and it really is kind of a tongue in cheek thing, bananas beat spades for long term reliability in almost all setups. If you have to use a Cardas or Mundorf speaker terminal to ensure your spades stay tight it kind of proves my point.