Hey I just noticed something that I found real interesting.
When I had the Spark Core on the included breadboard with the Chip Antenna positioned in the center of the bread board I instantly saw the Wifi stability of the Spark Core become unstable. The Spark Core constantly started Flashing Green > few mins > Breathing Cyan > few mins > Flashing Green > few mins > Breathing Cyan
My WiFi connection before putting it on the Bread Board had been really good so I was wondering what the hell was going on. So I assumed that it might be the WiFi antenna be affected by the metal grids in below the chip antenna.
I moved the Spark Core so the antenna was on the outside of the of bread board and the flashing Green led issue never happened again! So based on my experience, the bread board will cause the Spark Core to have a real hard time staying connected to the network and this will cause constant re-connection to the network which also is a almost guaranteed way to get the Spark Core to freeze up.
Maybe somebody can test the WiFi strength change with and without the Spark Core on the included bread board. Hope this helps others.