SOGs folders get the most flack, and some of it may be deserved. They are bit of mixed bag.
I have quite a few and have only encountered minor problems with a couple. Since most can be had for pretty steep discounts from MSRP all of mine seem to be decent value for the money.
At the low end I've got a couple of Twitch XLs and a Flash 1 & 2. Not bad for the money, depends a lot on personal need/taste.
None of mine have seen heavy use, so I'm not sure how well they would handle it.
There was at least one review (torture test?) where a Flash 2 was used VERY heavily. Far beyond what I would have expected it to tolerate, including batoning

. It wasn't in perfect shape when he was done, but it still functioned.
Overall quality seems to go up proportionately with price. The Tomcat3 is the most expensive one I have and its a darn nice knife.
When I finally picked up a TAC-1 auto I was pleasantly surprised. Very decent for $99.
There is far less criticism of the fixed blades. Most are well thought of.
Same with the MTs. I've seen little or no negatives about them.
The hawks seem to one area SOG really nailed it. I've read nothing but praise for them and they can be had at very reasonable prices.
I've only got one, a Fasthawk, but at $30 it seems a bargain.