It depends on how you slice it. If your expertise in this system is less than your others, it could cause real problems down the line. If a mistake was made in the setup, maintenance or recovery of the system because it's different, it would be just as easy to say it was negligent to use it instead of something that was well understood by your team. Trade-offs like this are made all the time, to claim negligence is to ignore the complexities of the situation.