USB Interfaces for use with MC6

Anyone have any experience with any of the following: Presonus Audiobox, Presonus Audiobox 22VSL, ART USB Dual Tube, Focusrite Saffire 6, Focusrite Scarlet 2i2, Focusrite Scarlet 2i4 or something by Cakewalk? Which one has the lowest latency? I have a laptop with Windows 7 64bit, i3 2330M 2.20GHz processor, 4.00GB RAM and 443 GB hard drive. These all fall in the range of $150-$200. I will be using it with Music Creator 6. Not doing anything fancy. Starting with acoustic guitar and vocals. Thanks for the help!