This is another one of those Lilliputian questions like which end of the egg do you break first or are super expensive speaker cables better than less expensive ones.
A very respected and elderly (i.e. quite knowledgeable & experienced) high end shop owner once told me, long ago, that bare wire was always best, provided the connections you're dealing with are amenable to this. What was unsaid and assumed, of course, was the obvious (e.g. provided you don't jam wire all over the place & have frayed strands sticking out here & there). If you're dealing with lamp cord (i.e. 18-gauge wire) and quality components (i.e. good connectors), bare wire might be just fine. However, if you're dealing with larger gauge wire, chances are bare wire is not in the cards.
Most high end shops like using high-quality banana plugs because these make swapping out speakers and other components for auditions quick & easy. In the early days, when dinosaurs still roamed the land, I used bare 18-gauge wire with the modest systems I had back then. Later, I graduated to high-quality banana plugs and high-quality spades. Presently, I use shielded 10-gauge speaker cables made with premium copper and high-quality locking spades at both ends. The spades are attached with premium solder and heat wrapped.
Last month, I had to move everything out of my living room for a home improvement project. This involved dismantling my sound system. After four years, the connections between the amp and speakers were as secure as could be. I had to use my nifty little McIntosh socket wrench to disconnect everything.
If I told you that I could hear a distinct difference between properly connected components using good quality bare wire, banana plugs or spades, I'd be lying ... to myself and to you. My preference is for properly attached high-quality locking spades because I feel these provide the best surface contact and the most secure connection.
