You're going to get less and pay much more in the long run going the custom route.
You have to hope that the person who wrote it doesn't disappear and is available long term to make modifications, fixes, feature additions, and provide general support for the product. The last thing you want to do to a programmer is hand them someone else's code to work on. They hate it
Either way this will get costly after a while.
Also, you have more issues to worry about as security goes with one person using the solution as opposed to many people using the solution.
With CARMA you are not stuck to a certain flow which does happen with some solutions as was indicated above.