The Good- The Plantronics Savi 7210 is the replacement of the CS510 and although both are very similar, you should expect:
Improved comfort with a softer ear cushion and padded headband
More sleek design that anyone wearing the Savi 7210 will appreciate
Improved noise canceling microphone to be heard crystal clear
12 hour battery talk time and 350 ft wireless range
The Bad- The Savi 7210 only covers one ear, so if your office gets loud, you'll be stuck with a headset not fit for your environment (See Savi 7220 for dual speaker option). In addition, if you ever need connectivity to your computer or mobile phone, you'll need to purchase a different headset. Overall- Based on comfort, ease of use, sound quality and battery life, the Savi 7210 is a solid headset for your desk phone.
Do you want the best headset? 
The Good- The Plantronics Savi 7210 is the replacement of the CS510 and although both are very similar, you should expect:
