Yes, Dstny Softphone works just as well on Mac as on PC. When you download your client there are two different programs to choose from, one called Softphone (PC) and one called Softphone (Mac) and both of these can be found at the top of this page. Login information can be obtained from your administrator or Dstny support.
Perhaps you are working at a computer right now? Transform your computer into a phone, a softphone, and obtain an all-in-one-solution with good sound quality.