Are they any good ? Any loss of quality suffered?
Looking at getting some as will make it easier to connect speaker cable as it gets a bit fiddly when you are trying to connect all your speaker cables?
I doubt you will notice any drop in audio quality by adding banana plugs. If you are planning on connecting/disconnecting the speakers from the cable regularly, then yes they are worthwhile. If however you will only be wiring the speakers up once and leaving them permanently installed, then I'd say save your money and don't bother with them.