The UI is rendered on the client-side web browser so responsiveness can very much depend on the size of the library against the speed of the hardware running the browser. There have been a couple of previous discussions on here about slow web interface response and generally it's been when old/slow mobile hardware is being used to run the browser.
I have a large library (>83000 tracks, ~8000 albums) and yes my tablet pauses whilst changing into the unfiltered tag and album views, especially after the library has been updated and the browser cache has refreshed but it's not unmanageable, my phone is much quicker being faster, more recent hardware.
If you're finding that your phone isn't fast enough to render the web interface you could avoid using the metadata-heavy tag and album views, sticking to the folder view or see how you go with an mpd client app like MPDroid or, as you say, BubbleUPnP which will be quicker purely because they're native apps rather than running in a web browser but they'll be less featureful.
I have a large library (>83000 tracks, ~8000 albums) and yes my tablet pauses whilst changing into the unfiltered tag and album views, especially after the library has been updated and the browser cache has refreshed but it's not unmanageable, my phone is much quicker being faster, more recent hardware.
If you're finding that your phone isn't fast enough to render the web interface you could avoid using the metadata-heavy tag and album views, sticking to the folder view or see how you go with an mpd client app like MPDroid or, as you say, BubbleUPnP which will be quicker purely because they're native apps rather than running in a web browser but they'll be less featureful.
