I think spades will give a better initial metal/metal contact when cranked down, and thus in theory yield better sound. They will also maintain that metal/metal contact longer before oxides build back up(gut feeling, based on pressure alone, cant say I know the exact kinetics of the oxide reformation in both situations). I prefer bare wire (solid preferred, though I also use Rat Shack 12 gauge stranded, Im not that picky with wire anymore) cranked down as tight as possible by hand. I also use bananas. Either way, I think differences in sound quality will be extremely difficult to discern even in a very high end setup(which Ive yet to hear so perhaps take that with a grain of salt). Ive not used locking bananas but Im sure Id like them and they will increase the pressure, but when you crank a spade the twisting motion will more easily clearly create fresh metal/metal contact, locking bananas will simply increase the pressure (normal force) but not in a sliding/twisting way bw the two surfaces. A sliding motion (spades) more easily creates fresh metal/metal contact. While bananas have sliding motion when you plug them in, the sliding normal loads are a lot less than a hand cranking down spades, at least with the spades I have and my speakers. While I havent done much speaker cable comparisons, Ive done a bunch of interconnect comparisons. Im fine with any “decent” copper interconnects. In my system I cant hear a difference bw a $30 copper interconnect (Audioquest Turquoise) or a $400 copper interconnect(Audioquest Emeraldx3, Harmonic Tech Truthlink). I have clearly heard differences in copper and silver interconnects though. Back to the topic - soundwise, my opinion is that I dont think the type of speaker connections can be heard. I would just go with what you prefer for whatever reason, or can get a deal on. To summarize, from a sonic performance point of view its about getting the most metal/metal contact initially and getting it to stay the longest. Periodically tightening or repostioning then retightening is a good idea. YMMV of course.