I got my 72MX195 last week, and am viewing SD and HD content from Brighthouse Networks (Tampa, FL) on a Scientific Atlanta 8300HD box, DVD content with a Samsung HD950 DVD player, recording SD/HD content on a Toshiba Symbio, and playing games with an XBox 360.
The image quality of HD content is simply amazing. The two demos that came on the Symbio are breathtaking, and the HD channels look crisp and clean.
SD content looks, well, OK (as its supposed to, I guess). One of my favorite channels, SciFi, is standard def, and it does look a little bit grainy. I fiddled with some of the controls, and the Sports setting along with the TheaterWide1 setting on Picture Size seems to work best.
The Samsung DVD player upconverts to 1080i, and the TV translates that into 1080p. I played the original Star Wars (episode 4), and it looked amazing. Hard to believe that movie is 30 years old. Serenity and Finding Nemo also looked amazing. Saving Private Ryan looked a bit grainy. I guess it depends on how the DVD is made, but considering you are taking a 480i picture all the way up to 1080p, it looks pretty good.
There is a VGA port for connecting a PC. You may want to check this thread
for more info on that.
The XBox is connected to a component HD input (Colorstream HD1) as it does not offer an HDMI option. I have the cable box and dvd player using the 2 HDMI inputs on the back of the TV. The XBox games on HD on this TV are incredible. I've played Call of Duty, Tiger Woods 06 and Project Gotham racing. The racing game in unbelievable. I could not detect any slow downs or framerate issues whatsoever.
The TV also has an ethernet connection which allows you to do several things: first, you can connect to a computer over the network and access shared directories for JPGs and MP3s, and play the files on the TV. Second, you can also give your TV its own email address and you can email it to schedule recordings. I still haven't got this part to work (I am having email configuration problems), but I was able to play MP3s. The MP3 player built into the TV is a little anemic, as it can only display a couple hundred songs, some encodings dont work right and the interface is not very friendly. It would work better if I find my favorite 100 songs and put them on a separate folder so the TV doesnt go crazy trying to read my 3,300 song library. However, I used a Slimserver Squeezebox to handle all my MP3 playing directly into the receiver, so this function is kinda useless to me. The TV gets its address from a DHCP server or you can manually enter all that info. The email configuration does not let you authenticate on SMTP servers, which is probably why I cant get it to work.
I have not tried the Theaternet IR cables to control anything as I purchased a Harmony 360 remote control which manages everything. The 72MX195 is in the Harmony database, and the only tweak I made was to add the PIC SIZE function to the DISPLAY button of the remote so I can switch picture sizes regardless of video input.
My biggest disappointment is the lack of Dolby 5.1 support over the HDMI cables. Even though the HDMI spec supports it, this TV only accepts 2-channel audio over its HDMI connection. The net effect of this is that the Digital Audio Out connection on the back of the TV is pretty much worthless except for content coming over the ANT1 or 2 inputs. I can tell as my first configuration had 2 HDMI cables (1 for the cable box and one to the DVD player), and one digital audio cable from the back of the TV to the receiver. This made sense to me, as I assumed the HDMI connections would supply all the necessary audio data. I was wrong. The receiver only detected stereo audio. The solution was to connect digital audio cables directly from the cable box and dvd player to the receiver, which kinda defeats some of the purpose of using a single HDMI single cable for everything. This is not a big deal though, as my receiver has 3 digital audio inputs, so the two I used plus one for the XBox served me right.
I purchased the TV from Crutchfield, and they have EXCELLENT customer service. I highly recommend them. Overall I give this TV two big thumbs up.