To me that's really the only bad part. Everything else is pretty smooth these days. I usually don't even deal with any paperwork or tricky waiver situations any more.
Yeah, signed up a long time ago and I never saw any drawbacks and it didn't cost me anything. I did initially get Hertz Gold through work but was free to use it privately. I signed up for the other ones myself.
Never - I have it through my own car insurance. If I didn't have that I would probably buy it from the rental agency, not sure if there are other sources that are cheaper.