I know -
Android Chrome can't cast music anyway from Plex Web (Mobile Chrome is limited to HTML5 video only) so is not a full alternative to the Plex App or Bubble. Potentially a useful addition though especially as the Plex App still seems prone to occasional irritating random disconnects from Chromecast - for me the Google Chromecast compatible apps (including Android Chrome now) are way more stable in that regard.
I've stopped using Bubble as a Plex client as-well - nothing wrong with Bubble, but for me disabling Plex's DLNA server is one of several tweaks that has improved casting stability (in terms of freezes and stutters) from Plex to Chromecast.
Most of the issues with Plex on Android are due to the fact Plex Devs are still using that V1 API which is really the PRE-RELEASE beta SDK. They claim the V2 API SDK doesn't have the code Plex needs to work but it doesn't seem to stop developers like Bubble from getting the job done.
Not a Knock but it would appear they are really an iOS centric project (the original fork of XBMC that has become PHT was mainly aimed at Apple Folks) and it seems as if they are a little short on Android Devs.
As a result they seem to be trying to solve all their issues via transcoding to overcome limitations of the default player they are using.
The issue is they don't have any real competition in the space they are in right now...
Bubble is better at the streaming but it doesn't actually do the server part by itself without a DLNA or UPnP server to aggregate. (perhaps this has changed recently I have not checked.)
So unless someone like Twonky or some other product comes out that supports CCast and does what Plex does they really don't have anything pushing them to take that next step.
I have even started using Yatse to connect to my XBMC box to get some of the features I want during playback.
