Sister got this for me for Christmas. I like it, it's a lot of fun, but I think Super Monkey Ball 1 & 2 were better. Okay, here is my take on the fifty minigames:
Alien Attack: Annoying control, no explosion of the aliens when you shoot them to give you satisfaction. Status: Meh
Asteroid Crash: Simple shooting gallery, but a ton of fun. one of the best in the bunch. Status: Great
Banana Catch: Ok, this one might be ok if it worked, but the controls are broken. Seriously. Status: Awful
Banana Thief: Hrrm, it works about half the time, but it's more annoying than fun. Status: Meh
Bugs Balance: very simple. but it executes it's idea well. Status: Good
Dangerous Route: Not for everyone. Very tedious, but a test of skill. Status: Good
Disc Golf: Urgh. The first couple of holes lull you into thinking it might be ok. Then it cranks up the suck. Status: Awful
Fish Catcher: Floaty and annoying. Status: Meh
Free Throw: Simple, but has a smidgen of fun. Status: Meh
Frog Ball: Ugh, with different controls it may have been something. As it stands, it is poo. Status: Meh
Fruit Basket: I liked it better in Mario Party 43. Status: Meh
Hammer Throw: Hard to get the timing right, but spinning a wiimote in a circle is always a good time: Status: Good
High Wire Act: Not bad, but not much. Whatev. Status: Meh
Home Run Derby: I'll be saying this a lot, but it makes you appreciate Wii Sports. Status: Meh
Hovercraft Battle: About the Same broken controls as Alien Attack. Status: Meh
Hovercraft Race: See above, except more confusing. Status: Meh
Hurdle Race: A kick in the pants, good stuff. Status: Good
Jigsaw Puzzle: Fun, racing against an opponents adds an element not seen in the Wii Photo Channel puzzles Status: Good
Jump Rope: Very short, but good in a simple, simple, simple way. Status: Good
Keepy Up: There's the roots of a deeper action/puzzle game in here. Status: Good
Monkey Bowling: THE SPIN IS MENTALLY RETARDED. WiiSports Bowling is awesomely better. Status: Awful
Monkey Boxer: Bummer, you can mover around the ring but the boxing is crap. Status: Meh
Monkey Darts: Very similar to real darts, I like it quite a bit. Status: Great
Monkey Fencing: What a disappointment. Finally a sword duel for you and your friends and the controls make no sense at all. Status: Meh
Monkey Golf: Wow, I really dislike it. A lot. WiiSports Golf is TOOOOOOOONNNNNS better. Status: Awful
Monkey Race: Not as good as its predecessors, but still enjoyable. Status: Good
Monkey Snowboard: Not bad, actually makes me want to try that EA snowboard game coming out. Status: Good
Monkey Squash: Huh? let's come up with worst way to play. Status: Meh
Monkey Target: Wow, I miss the old monkey target. This shallow thing gives it a bad name. Still, if you have played the awesome originals it's not bad. Status: Good
Monkey Wars: I like it but my friends don't. What do they know? Status: Good
Monkeysmith: Uh... that's it? Wow. Status: Meh
Number Ball: No monkeys, but pretty fun. Status: Good
Paper Sumo Fighter: I don't get it. Status: Meh
Paraglider: Yaaaawwn. Status: Meh
Racing Birds: I donno, I just didn't like it that much. Status: Meh
Red Light, Green Light: UURRRGH I WASN'T MOVING THE CONTROLLER STUPID GAME! Status: Meh
Ring Toss: Simple but it works. Status: Good
Rock-Paper-Scissors Attack: I don't get it. Rock-Paper-Scissors-Hammer-Helmet? Huh? Status: Meh
Scoop the Goldfish: Stupid and broken and lousy even it did work. Status: Awful
Seesaw Ball : Actually pretty good. Status: Good
Shepherd: When it works, it's pretty cool. But it breaks half the time. Status: Meh
Simon Says: Need Voicework. Status: Meh
Sling Shot: Okay, I can't hit anything. Status: Good
Space Monkey Attack: Starfox ala Monkey. good stuff, wish it was a full game. Status: Great
Spaceship Landing: Short and sweet. Status: Good
Treasure Submarine: I got bored with it. Status: Meh
Trombone: I suck at music games. Status: Meh
UFO Capture: Okay... whoop-de-doo. Status: Meh
Whack-a-Mole: It works like whack a mole, but somehow, it doesn't work. I donno, it's odd. Status: Meh
Yacht Sailing: I don't like, nuff said. Status: Meh
So in summary, five times the minigames of previous Monkeyball, but one fifth of the depth and polish of previous Monkeyball.
Maybe Sega plans on putting features back in for the sequel, like EA does with Madden.