What you need to keep in mind.
Believe it or not price is not the number one issue you should consider. In fact be wary of those offering steep discounts. The question in the back of your mind should be what corners are they cutting ordering to deliver a cheap service? After all every company needs to turn a profit in order to stay in business.
The first question you should be asking is about their infrastructure. Do they have the right pieces in place to protect your business when issues occur? It does not take a degree in Computer Science. Make sure they have two data center that are at least 150 miles apart. Make sure those centers are balanced for fail over. Lastly, make sure they have redundant upstream providers on both the PSTN and their internet connections. Every provider should be able to discuss this openly with you.
Next make sure your network is groomed properly for VoIP. Chose a provider that will work with your IT department or that can groom the network for you. Best practices may include physical or logical separation of the network. If the decision is made that your network can bypass that practice make sure you understand why. Not just that the provider can’t or won’t do the work to groom your network. The LAN is one of the top reasons most VoIP implementations fail.
Next make sure you work with your chosen hosted provider to insure you have the right internet configuration. That may mean you need to upgrade your connection or have some redundant connection in case of outages. You may also want to discuss how SD-WAN can enhance your internet experience
Now you can discuss features you need. The reality is that unless you have a system that will work the features don’t matter. If the system won’t stand the test of durability price does not matter. Consider carefully your options and ask good questions. A cheap service often cuts corners that will make a difference in your business.