Had mine for a few weeks now and I've had no problems that you describe. Mine gets it's feed from an external NAS and, for me, it out scores the Sonos for sound quality so well worth the outlay with a very nice iphone/ipad app :)
Got a pair of these floorstanders and I totally agree, the soundstage it throws is very good. I paid 200 quid for them in the nicer oak finish and whether they were £649 at any time is not the point for me
Cannot comment on the Dragonfly but the Explorer is a very good DAC especially if you like your music slightly warmer than neutral.
http://www.martinshifi.co.uk/news/208/offers-from-martins-hifi/
£115.00 is a bloody steal!!
EDIT- used to listen to Spotify through the Explorer and, yes, it...
If you shop around you can get the original Meridian Explorer for around the £125 mark which makes it excellent value. Whether the mark 2 version is worth the extra outlay for MQA technology only you can decide.
http://www.martinshifi.co.uk/news/196/christmas-clearance-sale/
I've had a few dedicated streamers over the past four years or so but the above, for me, has been brilliant. I run the Mac Mini into a Meridian Explorer DAC and I'm very happy with the results.
I use the Meridian Explorer with a Mac Mini with very good results and Amazon are doing a great deal at the moment :)
http://www.amazon.co.uk/Meridian-Audio-Explorer-USB-DAC/dp/B00BCJWTAM
Had a similar problem with a turntable with sound only coming out of one channel, sent it back to the dealer who found no issue so sent it back free of charge. Turned out it was my mistake :/ ...... guess it helps if you have a good relationship with your dealer.