For the most part, the distinction is in the decision to go with the corded or cordless headset. Audio quality will almost always be better when using a corded headset, so if that is your top priority, I'd recommend the Encore Pro. Also, you should not need a handset lifter if you have a phone with a headset button.
With that said, our cordless headsets do have excellent audio quality and noise cancellation. You also will not have to deal with interference between one CS540 to the next, as each has their own dedicated DECT frequency.
Please let us know if you have any other questions.