The ability to set up multiple extensions for different departments or locations without having many phones dedicated solely there was great! When you have an outage that prevents calls from coming into your office (or even just makes it hard/not feasible), they are very helpful with getting back online as quickly we possible can be achieved by them - sometimes within minutes of us reporting our issues!! They don't always tell how long until someone is available but when this happens I usually take their word at face value unless things look like otherwise happening too soon after me calling about my issue; then again if nothing comes immediately outta nowhere i know what's going through someones mind so maybe not worth trying?? Also no call forwarding which would've been nice since most offices do offer those services anyways- however being able get voicemail forwarded over another line has worked well enough thus far. The ease of use and the ability to customize the system to your needs. The customer service is also great. There is a lot of room for improvement, but the product is very stable and there is a lot of support and training available. I have been using this product for over 10 years and have never had a problem. It has been a great product for our business. The ability to customize the system to our needs and the ability to use the system in a variety of ways.