It's easy for customers, it helps me keep track of my calls in real time which makes things easier when I'm trying not be distracted by phone screens or ringing bells all day long! The software can sometimes have issues but they are very quick at fixing them so don't worry about your system crashing every now & then as this happens rarely (and usually only if you're doing something wrong).
Try using one first before deciding whether its worth investing into - there were some bugs we had while testing out their service however these problems seem resolved since our trial period ended unfortunately i cannot comment any further than what was stated above due too confidentiality agreements etc.