Kamailio SIP Server is very well suited if you want to secure your main servers; it can perfectly act as a proxy server and a gateway to your main server. It also does load balancing and call transfers easily based on the configurations done.
MicroSip integrates calls through my laptop, which is especially convenient and allows for continuity of my work so I can answer or make calls while updating notes or checking emails. It is particularly accurate with caller ID, call log and VM and DND features. Overall I enjoy using it and believe it is a beneficial tool to use as opposed to conventional calling.
As Kamailio SIP Server is an open source, the major impact is on cost; it's free to use compared to any other Softswitch or server in the market. You can also customize it to your need and use the features that you need, which is one of the major plus points for the Kamailio SIP Server. And one server is enough to handle thousands of calls simultaneously.
MicroSip is quite honestly the first call app that I have used which is integrated with a laptop but in terms of call quality and other features as mentioned such as VM, DND, call alerts, call log and caller ID these are all top notch. I would recommend MicroSip for any organization looking to save time.