There are two existing drivers for AWS MediaConnect - what's the difference and when should they be used?
There is indeed a free and a paid tier for Amazon AWS CloudWatch. More information about the pricing is available here: https://aws.amazon.com/cloudwatch/pricing/.
In short, there is a free tier, but this only provides a basic set of metrics that are only refreshed at a specific rate. Metrics will be charged as soon as you want to deviate from this (higher refresh rate or custom metrics).
As far as I can tell, using the MediaConnect API is free as you are charged for the services that you use and not how you initiate them.
Cloudwatch is a general monitoring and observability service from AWS that allows people to manage all the different cloud services AWS offers (you could compare it to an Element Management System from a vendor to manage their own products). Cloudwatch offers an API, through which you can get basic information about the cloud services that it manages. So the second driver that you reference here is to manage the MediaConnect service via Cloudwatch. The first driver you reference is the one that manages the MediaConnect service directly, i.e. it communicates directly with the API provided for the MediaConnect service. The difference? In general, the Cloudwatch version is more basic and probably serves you well if you are just looking for some monitoring of your MediaConnect services with DataMiner. The other driver that uses the MediaConnect API directly is going to offer you more granularity and control, and will be the one you need if you want to do more sophisticated things with DataMiner, such as automation and all that. I'm not an expert on the matter, so some people might be able to give you more details.
And while we are at it, just to piggy back on this question. I have heard that the AWS CloudWatch driver has various options in it to enable / disable the collection of specific individual metrics and to customize the refresh rate (i.e. the rate at which DataMiner goes and fetches updates for individual metrics), and that the reason for that is because the charge for the CloudWatch service is based on how much data you are pulling from it. Is that correct? And also, if so, does that apply as well to the MediaConnect native API used by the other driver?