Serviio

I have a TX-L47WT50B. It is lovely but I could never get the DLNA to work when reading from our home PC which was running TVersity. My son's PS4 doesn't help unlike the xbox 360 he used to have so I just bought a Roku stick and installed Plex on the home PC and client onto the Roku stick and it works like a dream. I hadn't realised just how nice Roku is with all the meta data being automatically scraped etc. etc. however the Roku device is yet another remote and it can be slow so it is a workaround as far as I am concerned. Ideally I would like to run everything using the TV itself. Today I happened to notice that the inbuilt DLNA on the TV now works when I pick the Plex server which is great - but of course none of the meta data is available which is a shame.

I have read great reviews about Serviio but I am struggling to understand whether there is actually a Serviio app I can install onto the TV. If not will it run in the same way as the Plex does via the TV. Additionally, does Serviio have a Roku application?

Thanks and sorry for being dumb...

No, Serviio is a DLNA media server and is played via the dLNA player built into the TV. No app is required on the TV, but this does mean you are limted to what metadata support the TV incorporates (most support very little, Title and thumbnails and ratings if you're lucky).
Yes, but better . Faster/more responsive is my experience.
No, but one of the Roku users may have some insight into other options that could be deployed (eg third party apps).