Love the pattern matching bits, the not pattern has been long overdue. Unfortunately, that's where it ends for me. Don't like the top level statements...makes it seem like I'm programming in a scripting language and makes me want to run as fast as I can in the opposite direction. Now, records... It will be another feature that is pretty useless and I'll explain why. When I'm writing an immutable type, my constructor validates the invarients based on business requirement.
