What sets the Rush models apart from the other folders in the Buck line is the way the blade engages in a...well..."rush." These are assisted-opening knives that feature Buck's ASAP system.
I have to say that I haven't always liked assisted-opening knives. But the Rush series has some very nice features. For example, unlike many other assisted-opening knives, the Rush models use a patented dual-spring blade pivot. This translates to a smooth-opening blade that engages fully on demand. I tried, but I couldn't get my Rush to partially open once the opening motion started.
Of course, as with automatics, the worst thing that can happen with an assisted-opening knife is that it can engage inadvertently. To prevent this Buck uses an innovative blade lock. The locking lever closes into a small notch in the blade and the blade is locked in the closed position, requiring the user to positively unlock it. I can state with great confidence that Buck's blade lock design works. While evaluating the Model 290 Rush, I made repeated attempts to "bump" the lock off, and I couldn't do it.
Beyond its mechanics, one thing that I really liked about the 290 Rush is that it's kind of cool looking. The Model 290BL Rush that I tested has a midnight blue skeletonized handle and polished 420HC stainless-steel blade.
The Rush doesn't look like a duty knife, and I think sometimes that's good. Having a knife that doesn't scream "cop" is useful, especially when in, shall we say, "mixed company."