[HTC EVO 3D] Impulses:
I just got around to testing my T-mobile adapter, unfortunately i didn't have any HD rips on hand, not even any recordings from the phone itself (and anything I record at night is probably gonna look less than stellar)... But I can still confirm a few things and share some facts.

The input the TV receives from the phone read 720p at all times, I can post a pic I took of this later with the phone side by side and the message clearly visible in the corner of the TV screen. Now, whether the phone can actually output any true 720p content or not is another matter... It could simply be upscaling everything from it's native 540p resolution... When you're at the home screen or in any portrait app the content appears in portrait on the TV, and in order to do that it's obviously downscaling (your screen's 960 vertical lines get crammed into 720).

That being said, I did play the Green Hornet and it looked fine. DVD quality I'd say (480p), keep in mind that it's a 3D movie compressed and with heavy DRM... So when played in 2D the source content really isn't any better than DVD quality. I also played a 720p trailer for Battlefield 3 and it looked pretty good, a bit low res at times but I normally game on a 24" PC display at 1920x1200 (or 3600x1920 w/3 displays)... So consoles or any game running at 720p or less on a 32"+ screen generally looks lower res to me.

However, resolution aside, neither the game nor the trailer (played inside the browser) ever looked pixelated to me. I noticed no jerkyness or obvious frame dropping, and no audio sync or skip issues.

There was however some overscan, the H in HDMI on the notification that shows up when you plug in the cable was partially obscured. I don't think the phone lets you adjust this in any way so if the TV doesn't you might have to deal with that, I'm sure it varies from TV to TV. Colors were a bit oversaturated (compared to the phone screen) but I didn't check if I have that HDMI port calibrated the same as the rest (which I do have color corrected). Either way, it wasn't drastic and it's something you can adjust for.

I tried looking for HD content within the YouTube app itself but I don't see any way to force a resolution within the app like you can with videos embedded within a website, is there a way? As a result, anything in the Youtube app looked pixelated and messy. I'll try and see if I can load some ripped HD content or my N64 emulator later (though that isn't really HD), maybe some other Android 3D games. Spiderman was a no go btw, got audio but no game, not even the main menu.

One thing I'll say is that the whole MHL thing is kinda cumbersome. If you're gonna watch an entire movie or a long pre-set sideshow I guess it's fine, but if you actually wanna hold the phone and interact with it then it's definitely kinda clumsy (I'm thinking gaming, manually flipping thru and zooming on photos etc.).

Having that adapter hanging off your phone with two more cables hanging off it seems kinda precarious, and HDMI cables are generally beefy and have some weight to them.

I was bracing the connector the whole time... As a result, I'm probably more likely to use my tablet (a Transformer) for TV output, unless I'm showing content that's already on the phone or something. I canceled Netflix so I can't test that anymore, sorry. Anything else anyone wants tested lemme know and I'll give it a go this weekend.

P.S. I wonder if the tablet version of Netflix looks better over HDMI output than the phone version, since it's playing content (or at least scaling it) at 720p to begin with, and they've actually advertised the output capabilities of the app on tablets. I do think if there's any limitations on the phone when outputting to the TV it's the app's fault tho, at worst it should play at the same res as your phone's screen which shouldn't look pixelated by a modest jump up to 1280x720 from 960x540. Chances are even over Wifi it's never playing at full res on the phone tho. /shrug