Why does everyone blame Benchmade for that chamfered hole? That is what original Blackwood design called for and that's exactly what went into production.
That's a good point, but I think people blame BM because they produced it with the chamfered hole. The chamfered hole might be nice for a limited # custom, but I think it detracted from the usefulness of a production knife (There is a difference).
Some great choices, that's for sure. I've owned/used all of them, except the Sage II. My comments:
BM 635: Very nice knife with a great blade to handle ratio. 2 "issues", IMHO. The chamfered hole & if you have lg. hands, like me, the handle's a little small. I think it's because of the curves & lg. finger guard area.
Bradley Alias II: Ergos are similar to the Seb. This is probably the best choice if you like the look & feel of a Seb, but don't want to spend the $. It's not the equal of one, but nice, nonetheless. I've had more Aliases than any of the others, except the Seb.
Buck/Mayo TNT: Another excellent knife with an "different" blade shape. Only issue for me (Me only) was the tip-down only.
CRK Seb: I'm assuming small. The standard that all other production frame-locks are pretty much judged against. Worth it? That depends, but I keep going back to a small micarta Seb.
I have not tried a Sage II, but have used/carried a Sage I & if the F&F is anything like the I (Which, based off of many posts, I think it is), it's an excellent choice if you want more "shape" to your handle, plus the full flat grind leaf shaped blade is a great utility type blade shape.
As I said, I keep coming back to the Seb. Now, if you want a larger folder, while the lg. Seb & Umnum are great, I EDC a BM 760. M4's hard to beat & I have a G-10 scale on it. Now I just need to flip the clip on it & I'm good to go.
Good luck with your choice.