Exchange 2016 - Limits and impact of Transport Rules (Mailflow Rules)

Sometimes, to solve complex problems, you have to use transport rules. But what are the limitations of this functionality?
I decided to cover 2 questions:

Part 1. How big may the transport rule be?

All transport rules are stored in the "CN=TransportVersioned,CN=Rules,CN=Transport Settings,CN=<Organization>,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<domain>,DC=<domain>" container. The rule itself is a XML that is stored in the "msExchTransportRuleXml" attribute.