Spade vs. banana plug

If construction and termination are done correctly I hear no difference. If I’m using bananas I prefer the ones that are made with a tightening screw that expands the contact points creating better contact.
Example: https://www.thecableco.com/diy-cables-and-connectors/banana/fp-202-g-banana-connector.html
FP-202 (G) Banana Connector by Furutech

I also hff ave all types,I let my speakers show me what is correct...old vintage amps the connections are really terrible. So that banana plugs ,but some dont .I like to switch equipment around offen....

In my mind I always thought banana was a more direct electron flow into the XO, but 2 reliable sources say spades are better

I don't have a preference in terms of the effect on the sound but do prefer the Z-plug or BFA style banana connectors. They provide a large contact area and the ability to slightly alter the diameter to fit what are often slightly inconsistent sizes in the diameter of the holes in the binding posts across brands.
LIke this -- https://bit.ly/3kam3Ct

I found that spades tend to get loss over time. A good tighten is required here and there. Banana plugs, especially the spring type, never get loss.
So, since I use only banana plugs.