They should consider switching, but the criteria needs to be outlined and weighted by the actual customer.

It all comes down to migration and maintenance costs and appetite for risk.

The primary question is will I get what I need on budget in the shortest time frame with option ABC or option XYZ?

The secondary questions are:

* If I need to extend the integration in 6 months with this solution what will it cost and how long will it take and do I have flexibility in who can do the work? * Can I upgrade to the next major version of ABC or XYZ and reasonably expect that my custom integration will keep working.