I'm checking out the UJ7700 with WebOS 3.5 and figured I'd share some thoughts.
First, I have found it to be very snappy and fun to use. It seems that everyday I find a new feature or use. Changing channels is quick, the extra content like Cast, YouTube Videos, and Web Browser is nice. I haven't used WebOS before so it might just be very similar to recent versions.
I'm a developer and enthusiast so I have started poking around with the apps and capabilities. As far as downloadable apps go, these are not available in WebOS 3.5: Pandora, Plex, ESPN, and SlingTV. The IP control is very good so I can do things like Turn On/Off, change inputs, and change volume.
Integration with iPhone is terrible... the app has to re-pair constantly and I would much rather have AirPlay. It's interesting though to navigate your phone from the TV.
A feature I was hoping for is to be able to record Live TV to a USB hard drive – correct me if it is possible to do this. I will probably never use the features to magnify, zoom, or capture the screen. I would like to be able to Pause Live TV or record some shows.
The Photos/Videos/Music work pretty well with my DLNA server. Plex DLNA server shows up and it's easy to find my recent TV and Movies here. I've compiled a music 'My Playlist' but I'm curious if you can have more than one playlist. Is the TV downloading this music or streaming it from Plex DLNA? I like how the music plays over the content and has a floating interface. As others have said, the DLNA UI could use an upgrade to rectangular images instead of squares. The MultiView UI could be updated too... looks like a computer instead of a TV.
The Magic Remote knows which input you are on. I have an AppleTV 3 and the remote can control it. With AppleTV 3 though, learning the magic remote was terrible. I had to use another learning remote to capture the Magic Remote and then have the AppleTV 3 learn from it. Holding the Down or Up button does not repeat correctly on the AppleTV 3 – it just goes really slow instead of fast. It would be nice if WebOS had a setting for those IR commands built-in its list. If you have a workaround please share. I'm holding out for an AppleTV with 4k.
The TV itself? Pure black is black, colors are incredible, but titles on a black screen are just ok.
A final thought... Is there a manual for WebOS 3.5??? I've had to basically discover all these features and questions myself.