I've worked with cloud services since they were introduced. indeed, many of the services my companies have offered since the early noughties were, ostensibly, cloud based. But Amazon confounds me. Their products are impenetrably complicated and totally unscalable out of the box. After years of paying them for services we barely used, they recently 'retired' one of our key servers for no reason and with no notice. Our reaction was to shut everything Amazon down and I will never work with their lousy service again.
And this was after a whole load of other issues, the biggest of which that it is totally impossible to cost or predict costs. I just KNOW that Amazon is far more expensive than alternatives such as dedicated redundant hosting.
And if this is business critical, it's more expensive than managed hosting, since you then at least know what your costs are and have someone to point a finger at when things go wrong.
Clearly, an ecosystem has risen around Amazon's cloud services, but it remains a highly specialised, esoteric and technical system to deal with.
Unless you have a large IT department, avoid at all costs. If you have a large IT department, what the heck are you doing dealing with Amazon ?