Soldered VS ...everything else

Not blind tested, but solder rather sucks.

I mean, it's really not that good of a conductor when it comes right down to it.

If you do use banana plugs though, I prefer the WBT method, where you hard crimp a sleeve onto the wire, and then you screw that to the connector. IMO, this is the method that is most reliable and will yield a corrosion free connection for the longest period of time.

I can see how spades would work better - using the pressure of the screw for connection. That is if you can get good compression between the wire and the plug. With banana you're relying on spring pressure.