The nakiri-bocho is highly suited to cutting vegetables generally and leafy vegetables in particular. It's all in the name - 'na' means leaf, 'kiri' refers to the cut. The nakiri features a tall, thin, double-bevel blade with minimal curvature. Because the blade is so thin these knives are not used for cutting fish or meat; the nakiri is a specialist vegetable knife pure and simple, but one which of course lends itself to other cutting tasks in the kitchen.
There are considerations. The nakiri can be a little heavier in front than other knives of the same length, although it's nothing that can't be gotten used to. It's possible the amount of chopping the nakiri does will mean shorter periods between sharpening. A nakiri usually must be teamed with one or two other knives.
Taking to any vegetable with a sharp nakiri is a genuine pleasure, however. Cutting techniques such as katsuramuki and sengiri are easier to execute thanks to the straight cutting edge. That flat edge also maximises contact with the board and minimises frustrating half-cuts. No more spring onion accordians! Juicy cabbage leaves dissolve effortlessly into finely shredded piles. The heel can be used for removing potato eyes, separating cauliflower and broccoli florets and other odd jobs. Shifting or scooping from the board to the pot or pan is very clean and easy. Believe it or not a sharp nakiri is great for slicing fresh bread or even rolled sushi.
As for blade profiles, think 'nakiri' and you will likely conjure up an image of a tall, squared-end vegetable knife. There are alternatives however and they share the same straight edge, thin blade and moderate length.
The kamagata 'sickle-shaped' nakiri sports a drop point. This knife originated in the Kansai region of central Honshu, it's said the sharp point is useful for the decorative cutting of the vegetables that feature prominently in local cuisine. Ask a Japanese knifemaker about this however and he'll likely shrug and tell you a pointy end is better for slicing plastic wrap.
The same could be said for the bunka-gata nakiri with its reverse tanto profile, similar in function to the kamagata nakiri but with a more angular appearance. There are very similar-looking knives called bunka-bocho, those have more robust blades and are closer in multi-purpose spirit to a santoku or bannou.
Nakiris commonly measure around 160~170mm in blade length, but you can find o-gata nakiri knives with blades of up to 300mm and over, a more agricultural length that does double-duty as a leek-measure, so you know you're cutting your leeks to fit snugly in the boxes you're using to send them to market. (Japanese knife culture is deep.)
Whichever form or blade length you choose, a sharp nakiri is a true pleasure in the kitchen and a knife many experienced users would never wish to be without.