Rope needs to always be held together somehow at the ends to keep it from unraveling. As with everything, there are tradeoffs between different approaches. The factors to keep in mind are:

• Rope will inevitably whip you or your partner in the eye eventually; so you don't want anything on the ends that is hard or sharp and could cause injury (such as metal, or melted plastic).
• You will be pulling your rope through a tight space several times per minute while tying; bulky knots on the ends will tend to get caught up, slowing you down and throwing off your rhythm.
• Some finishing techniques take more time than others; some rope kits last longer than others; consider how much effort you want to invest in a particular piece of rope.