As many have stated this really depends. Typically if the software is handling a standard business process, there is more value in having a commercial solution that is supported and managed by a large software company and standardizes your business process. If the software is directly related to the strategic value of the company and is unique, custom can be valuable especially if patents are involved. However it really depends, often in acquisitions we were buying customers and/or engineers and new we would eventually toss custom code. It’s important to understand what part of your company has value - customers, talents, IP (patents), etc.