Short answer: YES, they are all different.
Best way to figure out the differences? Brew with them.
Huge cop-out answer, I know, but its true. I've been skirting it for years; I just started digging into individual base malts, buying a bag of one malt at a time, brewing at least one SMaSH, switching it up when I run out. First was Weyermann floor-malted BoPils (SMaSH pils, saison), now I'm onto Best Munich I (SMaSH Marzen).
I was never motivated to brew single-malt beers before because I thought they'd be boring, but the results (so far) have been delicious, AND have given me perspective on my ingredients.