Purifi and Benchmark measured the different types of connectors and found the bananas the worst measuring. There was an article/interview about this when Purifi was releasing their first amp module. Benchmark also mentioned the same in some article they wrote. They like SpeakON the best.
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.