I've had a # of both BMs & Spydercos. That's such a tough question as to which ONE someone would pick, plus it's SO subjective.
As for my favorite BM, hmm, that's a tough one. If the Grips had G-10 scales, they'd be great. But they're still a pretty good deal.
On paper, I'd say my favorite Spyderco is the CF Stretch 2 ZDP, but I don't use mine. I'd like to get the FRN Stretch in ZDP as it should be lighter & a little easier to carry. Right now, my favorite Spydy's the Lum Chinese ZDP.
As for the Salts, I've found H1 to be a very good steel. Aside from the obvious, it doesn't rust, it holds an edge very well. I'd say the only negative is that is scratches easily, but then solid ZDP-189 blade's seem to stain easily (Not rust, stain), but there's nothing like ZDP's edge holding just as there's nothing that compares with H1's rust resistance.
I have 2 Salts, a LadyBug 3 & a Pacific & I really like the Pacific. It's the same size as the old Endura & it's noticably lighter than an Endura, too (IIRC, 3.0 oz vs 3.6 oz).