BK2 - ESEE5
Both are good knives
BK2 has a little amount of storage in the handles, sort of like the HEST
BK2 has a straight spine, ESEE5 has a couple degree slight drop from the handle
ESEE5 has an exposed pointed (glass breaker) pommel, BK2 has a profiled tip to the handle
BK2 = flat grind, ESEE5 = sabre grind
http://en.wikipedia.org/wiki/Grind
You can find BK2s for about $60, ESEE5s for about $100
As mentioned about the BK2
You can get different slabs
You can get different sheaths
They are very similar otherwise
Warranty:
ESEE - "No Questions Asked Warranty. If you screw it up, break it, or cut it in two with a cutting torch, send it back and we'll replace it. Warranty is transferable. In other words, we warranty the knife no matter how many times it's been traded, sold or given away. We don't ask for a sales receipt, date of purchase or where you bought the knife - No fine print and no hassles. If you have a problem, contact us. "
KaBar - "KA-BAR Knives, Inc. (the “Company”

warrants, to the original purchaser of the knife only, that this knife will be free from defects in material and craftsmanship under normal use and maintenance for the lifetime of the original purchaser. This Limited Warranty does not apply to any failure of, defect in, or damage to the knife caused by normal wear and tear or by improper use, including throwing the knife, using the blades as a can opener, chisel, pry bar, screwdriver, digging tool, or for any heavy work for which the knife was not designed."