Does the brush give definition and do the bulbs on the ends pull or snag your hair?
The bulbs don't snag at all! It's waaaaaaaaay better than any similarly-looking brush I've ever, ever used. It doesn't even seem like the bulb is one thing and the bristle piece/length is another thing. It seems like each bristle-bulb is all just one seamless object.
I have gotten SOME definition if I detangle the section with it first, then pull it down through my strands at the right angle. When detangling, I use a flicking kind of motion as to minimize tension and pulling. Once a section is detangling, I can hold the brush at a very particular angle, pull the brush down through the ends, kind of curling the hair around the brush as I do, and then I get definition, clumping etc.
I'll see if I can find a video that demos the move/movement when defining.
That said, I couldn't tell you if it's GOOD for defining. It might be laborious or tedious or not-that-great for defining. I don't know because when I define my hair, I do the shingling method with my fingers. I should learn, though, because if I could define with any brush, that might be a game changer!