The disappointing thing about DKJB (I'm assuming that is the one you meant to ask about) are the boss battles are extremely repetitive. There's maybe just three to four different boss "skins" and maybe one or two different ways to dispatch of them. There's nothing really new way to dispatch of them.
That said, it's a hell of a lot of fun controlling DK. Once you really get used to the controls, you'll get this sense of amazement as you see him flying through the air building up combos. The level design is simply fantastic. It really is unlike any other platformer I've played barring the innovative control scheme.
If you like the old arcade mentality of "beat it over and over for the top score" then the game's perfect for you. First time running through, the game is pretty short, but trying for the higher medals really has you going over the levels trying to get that last banana. And going back to the level design and the fun control (it doesn't really get tiring), that isn't as tedious as it would seem.