USB Sound Cards: Omni Surround Pro 5.1 vs. Recon 3D USB vs. X-Fi 5.1 Pro

Update [2014-05-16]: I updated some thoughts below on sound quality. [Update 2014-09-14]: Added a pretty big caveat to the Omni Surround. I am a bit nuts about external USB sound card / DAC /AMP combos.  I’ve bought 3 from the same manufacturer.  They are all part of the Sound Blaster line of sound cards from Creative. […]