Bates M-8's are almost identical to the Khybers, and are another good option. DS loves his, and is getting a 2nd pair even over the other options available.
And you can get them through AAFES, etc.
Most important thing is fit & comfort. Second is do they have decent traction. (one of the options for 2015 did not, and cadets regretted their choice)
As the boot letter normally mentions, fit is critical, and most wear 1-2 sizes smaller than they think. If the heel or sole rubs when they walk, the boot is too big! If you scuff your foot on the floor, and your toes hit the front of the boot, it's too loose or too small one.
Most find that if your foot is measured by a Brannock device(???) the fit will be dead on, or very close. And usually smaller than they would normally wear.
The reality is that most of the options are good if it's a modern tennis shoe type construction (Kyhber, M8, Nike, Oakley, etc).
The 2nd pair issued on R-day in past years was a cheap, old style boot. Even the 310's were ahead of them. DS keeps his as inspection boots.
Khybers:
M8:
310: