the original bk9 was almost a quarter inch thick. I will be surprised if the new bk9 is thinner but it sounds like people are saying it is thinner. it use to be more like a battle rat. for edge retention I like sr101. I really decided that more recently as I notices m6 has held up better than most my other knives. the becker and cold steel line used the same steel and had great edge retention. the first knife to dethrown the recon scout was the m6 but now the choweiler is king for me. edge retention on s7 is not the best but if you want strenght than s7 is a good choice. another plus for scrap yard is their design. I like the handles and spine on my scrap yard knives. they are the most comfotable design and perfect for chopping and batoning. the sod is a better choice in the long run, if you change your mind you can sell it for at least your cost. I just sold three scrayard blades. these knives never loos value. I just bought a nmfbm and hope to buy a small swamp rat soon. now my tan sod might be the coolest knife ever. I hope it comes soon.