Michal,
I agree with you, at the end of the day, it comes down to trust.
- Do you trust your personnel?
- Do you trust the vendor has built a stable, reliable, "bug-free" solution?
- Do you trust your change management process?
I would also like to add a comment about your "there is no time" to learn a technology. I'm sorry, but if you don't have time to learn it, you shouldn't use it. You should never rely on a piece of software to do your job for you. How many times has we seen in our careers where people tried to do it themselves, and the rest of us have to come in to fix it? While I enjoy the job security, it is usually painful to fix, and embarrassing to the person that did it.
This entire conversation has been very interesting to be part of, and has alot of compelling reasons to both use the solution and not use the solution...but the decision will always come back to trust.