I've also been using Spotify on my Squeezebox Touch which has a (fairly rudimentary) Spotify app. I've been able to stream GMusic to the Squeezebox using Cast To UPnP/DLNA for GMusic which makes your UPNP devices show as ChromeCast devices so you can just use the ChromeCast button in the GMusic app. This works well though you don't get gapless playback unfortunately.
Signed up last night when I saw the notice after uploading a couple of albums to GP Music. I'm also in the middle of a Spotify Premium trial as well.
The Google implementation integrates really well with GP Music app letting you add albums or tracks directly to you music collection where they appear alongside your uploaded and bought music. I've also found the GM mobile streaming (over 3G) to be more reliable than via the Spotify app so I'll very probably go with this over Spotify.
£8 per month is embarrassingly cheap considering the amount of use I'll get out of this. They don't pay much to the artists as it is.
My Nexus 7 has the annoying auto-brightness all over the place problem and has had a few random reboots (though this might be down to a particular app - HD Widgets seems to cause a reboot each time it updates).
Haven't noticed any problems with battery life.
Was pretty unresponsive immediately after the upgrade but seems fine now - lots of apps putting out 4.2 updates so maybe this has helped?
Bought the 16Gb version and pleased to see they're equalling the Kindle Fire models on memory now.
I've never got near to filling mine up as I stream everything from my NAS at home and just download some bits and pieces for long journeys.
Would rather have had the extra few months use of it than wait for the 32Gb model - you can spend forever doing that.
Bought these and was very disappointed.
Nice looking design but the bass was so boomy it really took me out of the music. The opposite of a transparent sound.
Was a real relief when I went back to my Sennheiser CX 300 II buds (a couple of quid cheaper too) :-(