The methodology produces an automated, high-fidelity conversion process that can be used to produce a .NET solution for the legacy system – a solution which can be verified to be correct, is reengineered to conform to your architectural standards, and takes advantage of what the .NET platform has to offer. Having such a process minimizes cost, risk, and disruption without sacrificing quality, control, or time to market. It will produce an end product that will flow seamlessly to the user community -- with negligible disruption to operations and minimum re-training. This is not the case with the COTS option.
Upgrading a legacy system can be difficult and expensive, and it is important to consider your options carefully. One option that sometimes comes up is to replace the legacy system with a commercial-off-the-shelf (COTS) package of similar - but seldom identical - functionality. In many cases, a suitable COTS replacement does not exist, so the decision is easy. However, in some cases a reasonably good package replacement is available and the COTS option is conceivably possible. In addition, there is often a particular appeal to the COTS option because the package may include some nice features and the implementation cost seems easier to estimate: licenses and implementation support, simple enough. However, beware that there are many hidden challenges, costs and risks associated with a COTS implementation. Compared to other options, these costs cannot be ignored.