I've been using the new AMP since it came out. I also tried out the Beam for a short time and thought it was good for what it is. I'm music first as far as what I care about the most and I was hoping to have the AMP do double duty. I'm using the AMP with Revel Concerta 2 speakers which are $900 and highly rated plus Sonos Sub and One SL rears. It's been great for music and for home theater and the phantom center channel is actually pretty decent. My only source for everything is 4K Apple TV connected to a 55 inch Sony X930E. For music to get two channel sound I had to switch the Apple tv to stereo and turn off the Sonos rears.
The ARC made me curious so I ordered it and received it today. Setup and connecting the sub and rears was very smooth. When I tried to do Trueplay with my iPad it said there was a network issue. After restarting everything, plus some cussing, I decided to try my iPhone to Trueplay and that worked right away. Otherwise super smooth and easy setup.
The ARC is really great for home theater and better than the AMP and Revel speakers. Everything sounds like one piece between the sub and rears and ARC. When I stopped using the Beam and went back to the AMP I noticed the front sounded disconnected from the rear but I got used to it. Not the case with the ARC which has a very cohesive sound with the Sub and rears. I also had to turn down the volume on the rears which is interesting. The ARC has a nice wide soundstage and I could hear the effects of the side speakers too.
Dialog is very clear even without turning dialog enhancement on. Detail is also better. Sadly I don't get ATMOS from my ATV and Sony TV. Music of course is not as good as the AMP but it's ok for background music. I'm going to setup a two channel system just for music and probably add a turntable. I might keep the AMP or get something different for that. Of course the ARC also takes up less space and has voice control which I will use. So overall very happy with the ARC and looking at all the other soundbars out there I'd rather have this. I'd even say $799 is not bad for what you get if you look at similar products.