i have carried a benchmade spring loaded folder for the last four years, its been to Iraq and Afghanistan with me, the black finish has worn a little bit from the sand and my pocket. I have resharpened it twice and it still functions flawless. Not the fastest push button opening knife, but decently fast. I carry a gerber tanto blade spring loaded knife when not in uniform because it isnt as beat up as my benchmade. it is a little bit of a heftier knife in your pocket, but it is rock solid, sharp, and fast opening. Both are half serrated.
Benchmade
http://www.bladeops.com/Benchmade-9051SBK-AFO-II-Automatic-Knife-Black-T-p/ben9051sbk.htmGerber
http://www.bladehq.com/item--Gerber-06-Automatic-Knife--1472