Is there a bad side to a RTW law? I don't know nearly enough workplace law (even anecdotes) to comment. I know I work in an RTW state as a teacher and the unions here have little to no power, more a trade organization. The NEA is only strong in the heavily Democratic areas.
Can anyone with knowledge on RTW vs At will shed some light on this?
Yes, it is a Federal infringement on a state's rights. The Fed's would be correct if they pass a law affecting forced membership in a union for Federal employees. Beyond that, it is the Fed's taking power from the states. The reasoning doesn't make it right. If a state wants the economic benefit of RTW the people of that state can approve it.