I currently have four SOG knives and one of their machetes.
- Mini X-ray: this was my first SOG, and is still my favorite of the SOGs I've ever bought. Small, light, and (to me) a beautiful little half-serrated tanto blade and lock mechanism. It is actually one of my favorite knives, and I won't ever get rid of it.
- Flash II: When it was new, and before I'd had exposure to so many much better knives, I thought this knife was great. Light, blade held a decent edge. But after six months of EDC, the auto-assist open feature got...tired. Only way to explain it. When you tab it open now, it doesn't have anything like the snap it had when new. That's crap design. Secondly. the cheap plastic body cracked when I happened to drop it at one point and it landed on the butt of the handle. Lastly, good lord, the blade play. Front back, side to side. TERRIBLE construction. Wouldn't ever buy another one, too many other great knives at this exact same pricepoint that won't have any of these issues.
- Tac-Auto: Ehhhhh...you know, when I bought it, it was the best knife I owned (I believed) at that time. The body is incredibly thin, I thought it was cool because it says "Caution: Full Auto LE/MIL" on the side, and the blade does look wicked when you press the button and it snaps out. But you know what, this knife has really weakened in its opening ability. You depress this small button and the blade is supposed to whip out. Well, it is noticeably slowed down, and it also only did EDC duties for several months (I rotate quite a large number of knives) and wasn't really abused. So, that to me says poor quality. I wouldn't buy another one of these, even though they look cool. The blade on mine was decent, oh yeah, except for the HUGE blade play when locked open. I just never had a ton of confidence in this knife. It sits in my knife box these days. A shame.
- Seal Pup: I have one of the new ones that has the Elite handle. I got it super cheap during a Groupon special that was running a few months ago. I got it for $35 shipped, which honestly, is about all I would pay for this blade. That's not to say it's a bad knife, it's just that I don't really have any need for a fighting knife, which I think this knife would serve best as. I have so many more competent bushcraft/woods knives, which would be my primary use for a fixed blade. But if you were a super stealth black ops SWATSEAL Delta Commando operator, who needs to sneak up behind the guard at the enemy compound and shiv the guy in the neck for a silent take-down...this knife is for you.
- Short Machete: I have that short machete they make, with the little ridged butt-cap (in case you need to beat some brush over the head, I guess) and it's decent. It's done everything I've needed a machete for. But then, my Chinese Fiskars Gerber machete has done the same thing, and they both cost the same, so there's nothing this blade really offers that says "OMG Buy the SOG!" over other offerings.
All in all, I don't really see myself buying any more SOG products. I just don't really feel any connection to the company's products or their message. And definitely, as others have said, there are better products available at these exact same price-points, so why bother? Your mileage may vary, but these are my direct experiences with these products.