A new HW-E450 user here... Picked a refurbished unit up from TigerDirect for about $150 and for that price I couldn't be happier. Maybe at the going new rate of $260 to $300 I wouldn't be quite as happy, but overall I am very satisfied.
I connected it to my system which includes an LG 47LW5600 TV, DirecTV HR24 HRDVD, a Panasonic BluRay player and an AppleTV which I use infrequently for AirPlay streaming from my laptop.
As for mounting, I went to the local home improvement store and picked up some flat-bar, 1/8" thick, solid (no holes), 1-1/4" wide. I was able to cut three strips that lined up with the mounting hardware for the TV and sticking up above it such that a third strip goes across/between them and the soundbar mount is attached to that. Took just about an hours worth of work to do that and resulted in the soundbar nicely sitting on the top side of the TV. The mount is a Monoprice articulating arm mount as the TV is located in a corner so this worked out very well.
I read lots of the information here, but still one thing caught me by surprise... The LG includes HDMI-CEC support as well as ARC, but I thought that if I connected the DirecTV receiver to the soundbar HDMI-IN, and the HDMI-OUT to the TV's ARC compatible plug that the video would flow from the receiver through the soundbar to the TV and the audio would simultaneously flow back to the sound bar. This is not accurate. To use the device connected to the soundbar's HDMI-IN I have to put the soundbar in HDMI mode. No major problem, I just moved the AppleTV to this jack since we seldom use it and it simplified the operation for everyone else.
How does it work? Very well. While I *wish* the LG TV would turn the soundbar on when you power the TV on, this is my only complaint.
Once the TV/etc is powered up, I can either just manually turn on the soundbar, use its remote, or use the LG remote to hit the SIMPLINK menu and change the speaker from TV to HT. I can certainly live with this, because from that point on the TV switches over to it, the sound bar switches to TV-ARC and integration is perfect. The soundbar even turns off when I turn off the moment I turn the TV off.
As for sound quality, well, sure it is no home theater setup, but the difference in quality compared to the built-in speakers is huge, and so far this is only from watching a few kid's shows on NICK, a little Food Network and some cable news shows. Once we drop a real movie in and kick the sound up I expect to be very impressed.