I dont recall reading any posts on the smartphone (iphone in my case) controller app for the Panasonic Viera TVs but I've given it some time and I find it really useful.
Every feature on the remote is available via the app, plus more. In fact I would say the response time is faster on my phone, especially navigating thru the viera link menus. With the one exception that the playback buttons in Netflix/Amazon arent as responsive. There is a keyboard input feature on the app which saves me having an extra keyboard around or spending 5 minutes typing in passwords. My wife got a kick out of being able to stream photos from her phone to the TV by pushing a few buttons.
The app is available for free in NA for iPhone and Android phones. Just FYI, the UT50 series requires either the optional wireless dongle accessory or the TV has to be connected to a wireless router. In my case, I happened to already have my UT50 wired to a router which had an Airport Express connected as well and that worked fine.
I know this isnt useful for everyone since the UT50 is not inherently set up for wireless and some people would rather stick with the remote. I downloaded the app on a whim but now Im pretty much using it exclusively, I think it's very cool user interface that has not received a lot of exposure. Here's the link from the Japan site with details on features and set up: