Nowadays, pretty much every phone system will offer basic capabilities such as call hold and transfer, do not disturb, and call forwarding. But when you want to upgrade your phone system, it makes sense to look at where you are going to get the most feature-rich system for your budget.
There are some more advanced features that your new system should definitely be capable of, such as 3-way calling, single-number reach, voicemail-to-email, speed dialling, and presence which enables your employees to easily see which of their colleagues are currently on the phone. If the nature of your business involves you frequently receiving calls from customers, you should definitely be considering systems that offer an automated attendant as well as hunt groups. These efficiently guide callers to the correct employees.