Connecters do make a big difference. When I first discovered this I was using banana's on the end of spades, I was comparing amps and speaker cables and I wanted to switch easily, and once I got rid of the banana's, I realized I had really wasted my time, I did not realize just how much I was losing.
Sometimes, hooking up bare wire is a major pain, especially fat stranded wire into fat binding post where the wire is too fat to go into the hole. It is really a pain because the connection is important and sometimes you just can't get a good one that stays good. This is where spades come in. A spade really is a good connecter, especially high grade ones. You can really lock down onto a spade. A lot of good speaker cables are too fat to go onto binding post, and you have to get something to terminate the wire to so you can get a good connection.
Every time I have been able to get rid of a spade, I have noticed an improvement. Can't do that with all cables, but if you pay attention to the quality of the connection, It can really make a difference in very practical use. Often times, one more expensive speaker cable will sound a lot better mostly because it is made with a better connecter. Banana's really are , in my humble, and cheap, experience, "that bad". How easy is it to get good sound?