We've probably explained a dozen times why we think Са́мбо (aka Sambo) is a badass grappling art on par with our style, BJJ. So much of the technique is similar or the same, yet Са́мбо remains distinctive.
One thing we love about Sambo is the emphasis on quick submissions and lock-flow type joint attacks. Unlike BJJ, which, in its current state as a sport, emphasizes extensive guard-play (and minimal little takedowns), Са́мбо is fast, guard-play is minimized, and the subs are quick and sometimes violent. Of course, BJJ is about quick subs as well, but it's also a lot about sweeps from guard and guard passing (especially at the world class level).
Check out this very tight flow from an americana-type sub to an armbar. Then check out another that illustrates a reverse armbar to a gnarly wrist attack. You've seen all of this before, but not quite like this.
Sidenote: Bloodandsweat.ru is a pretty burly site with great original content. Too bad my Russian language skills don't exist.