As far as further services are concerned, Samsung has been unable to provide details beyond "watch this space." Spotify is the most glaring omission at this point, but Sonos supports a much larger range of services, including Spotify, Rdio, and Beats Music.
The system is controlled by the Samsung Multiroom app, which is relatively simple to use, particularly in the way it handles multiple speakers. Adding new ones was a snap, and while the speakers have an "add" button on the rear, the autodetect was so good we never had to use it. The app also lets you click a button to put two speakers in stereo and swap left and right if they get connected the wrong way.
When it comes to playing music there are a few quirks though -- for example occasionally it would prevent us from pausing the playing track. Also, pressing the big "Play" button doesn't automatically play the last thing you listened to, you need to press the Menu key above to get something playing. Creating playlists is also currently problematic as you can't add tracks from Amazon, and there's no on-the-fly lists without opening a playlist first. It's also unclear at first how to access playlists -- you need to swipe to the left.
One missing piece in the controller puzzle is the lack of a desktop app. Squeezebox had one, Sonos has one, and even Play-Fi will get one, eventually.
Given the price similar price, and the fact that we didn't have a Play:5 to compare it to, we did most of our listening comparisons with the Sonos Play:3.
As a background speaker the Shape M7 does its best work. Unless you sit very close to the speaker -- close enough to lick it perhaps -- you're not going to hear true stereo from a device that measures only a foot across.
With music, the M7 showed more detail in the upper-mids, and even when playing the low bit-rate Dig Music radio station there was more air and space than we heard on the Play:3. The Samsung had a more defined midrange that flattered voices in particular. There was also more of a bass thump from the dedicated woofer on the Samsung, which served it well during rock tracks.
Hooking it up to a Samsung F8000 TV was very successful and easy. The two devices recognized each other quickly and we soon had lag-free audio via the speaker. The speaker did a better job of music ("Red Right Hand") and movies ("Mission: Impossible II") than any TV speaker we've ever heard. If you're looking for a "sound bar" which also does music, this is probably your best bet besides the Pioneer SP-SB23W -- be aware there is no subwoofer option on the Samsung though.
While you can make a stereo system out of the M7, it's not something that would please audiophiles. First, activating "stereo mode" immediately raised the bass EQ by a quite noticeable 3db (though it wasn't difficult to adjust it back). By Samsung's own admission this speaker features a "stereo effect" rather than actual stereo. While you can hear things coming out of the left and right speaker, there is no imaging to speak of at all. Vocals don't come out of the middle but are seemingly thrown out as if by a ventriloquist--it's hard to know where they're coming from. However, this isn't a problem unique to Samsung -- the Sonos Play:3 in stereo configuration also had phasing issues when placed side by side.
Sonos has had 10 years to iron out its system, and Samsung's has been on the market for only 3 months. As a result you've got to expect some growing pains, but the Samsung's signal was a whole lot more stable than the Phorus Play-Fi system, for example, which had problems when presented with a wireless-heavy environment. There were occasional dropouts with the M7, as we've found with the Sonos system in the same room, but the ability to stream hi-res 24-bit files with no real problem is a feather in Samsung's cap.
We've seen many streaming products come and go recently: Logitech canned its Squeezebox products, the Google Nexus Q died before it even begun, and Sony's NS310 wireless product disappeared the year it was released. That's one of our biggest questions with the Shape platform: Will Samsung stick it out and support this system over the long-term? After only three months in, there's no way to say, but the M7 is certainly a promising start, especially when it comes to sound quality.