Don't listen to all the knife snobs who consistantly put down CRKT, they do the same with SOG and pretty much any other brands but Benchmade, Spyderco, and Kershaw. CRKT makes a fine knife for your average knife user who doesn't demand the top shelf materials. I have owned many of there products over the years and have yet to be dissappointed considering the price point. The M-16 is a nice design, I know a guy who has quite literaly abused one for about three years now, he has the tanto version and carries it everyday as his only knife. He prys, scrapes, and uses it like a screwdriver as most non-knife people tend to do, and it is holding up splendidly. He brings it by every few months for me to sharpen it and he couldn't be happier with it.
If you plan on using it roughly and want a strong tip then the tanto is your best bet, if you like a thinner, sharper tip for more precise tasks then the spearpoint is your knife.
I myself have been looking to pick up the M-21 even though I own many Benchmades, Spydercos, Kershaws, ect.
I had the opportunity to pick up a M-16 spearpoint for $25 at a local knife shop the other day but passed it up and someone else bought it the same day. Still kicking myself for that one.