^This.
If you need/want Wifi (and typically, by default, Bluetooth), then the motherboard with onboard Wifi would be the best solution.
A quality Wifi adapter will set you back a minimum of ~$30. While USB solutions have come a long way in quality, they still have some flaws - and that's in the quality offerings. The cheap/generic Wifi dongles won't achieve anywhere close to the same throughput, can have connectivity problems and typically lack driver support.
Considering the board at $120 + a quality Wifi adapter at $30 minimum, you're in for $150+
Since the Gigabyte board has a variant with Wifi/BT for +$25 (and typically Gigabyte have some solid offerings), it's really a no-brainer IF you want Wifi.