Oct 2016I bought a CS540 to replace my aging CS70NC that was failing fast. I looked into replacing the battery, and maybe the crumbling earpiece, but the cost was more than I wanted to spend to rehabilitate old stuff. I had been very satisfied with my old Plantronics unit and was glad to see that the company was providing an improved model. The CS540 base unit is smaller, has more visible indicator lights, improved switches, and is compatible with the handset lifter I already owned. So I ordered it from Amazon and two days later was again enjoying clear sound and amazing range. I work from home and often roam during phone conferences (more coffee, fetch files, etc.). My old Plantronics headset let me get a few rooms away before losing the signal, but the new CS540 lets me get to every room in my 2 story house with no noticeable loss of signal.The CS540 can be used over-the-ear or over-the-head, but I find the lightweight earpiece to work very well resting on my ear. The mic boom is slightly adjustable toward my mouth, and very adjustable up and down. So finding a comfortable position is easier than with the older model. It's easy to forget that I am wearing it.The CS540 sound quality adjustment switches are much easier to understand and use than the older model. A call to the Plantronics 1-800 number is a quick way to get the settings correct, followed by a call to someone willing to answer your questions about "how does this sound?" In my case the switches required only minimal adjustment from the factory settings. The person I called said she could not tell I was speaking over a headset. And I could hear her as if I were listening on the phone's regular handset. The CS540 is a very well made device.My only minor complaint is the lack of printed instruction manual. The unit comes with a multi-language foldout that is adequate for the initial connection to a desk phone, but it doesn't clearly explain other features such as indicator lights, headband attachment, advanced setup switches, etc. A more complete manual is available online, but I saw what seems to be a few errors related to the advanced switches (for wide-narrow band radio settings, and headset pairing). Despite the errors, I was able to figure it out well enough such that I spent no more than 10 minutes from the time I opened the box to when I was all done with installation and setup.If you spend a lot of time on conference calls I can recommend the CS540 as well worth the extra cost. I've used many other headsets, both wired and wireless, and also Bluetooth, and none of them come close to the quality of Plantronics products.Also: don't skip the automatic handset lifter. It's a clunky looking gadget but it works very well.