Yup, I got everything from various game center's UFO catchers. It's kind of hard to approximate my success rate because I've developed skills to catch small plushies and large, relatively light boxes. Medium sized plushies are a little harder to get but if my mood is good and my luck is decent, I could get one out of 10 tries (100 yen per try). As for big dolls... I've never had one. The stuffs I caught above probably worth about 3500 yen, and I think it's pretty darn cheap because that Hatsune Miku figure costs 2800 yen if you buy it at stores in Akihabara.
It started 2 years ago when I visited Japan over Thanksgiving break. As you would expect, Japan's game centers are filled with game machines of the latest technologies. I'd love to post a lot of pictures of the machines but photos are not allowed inside game centers. I'm not sure what the exact reason is but I think it has something to do with the gamers' privacy.
Unlike in other countries I've been to, UFO Catchers if Japan offer wide varieties of goods, and almost all of them are possible to get. In the US, the UFO catcher's hands are too weak and I've never seen anyone successful. Here in Japan, the success rate of getting something out of these machines is much higher. It makes you happy and confident that you could get something else the next time you play, and in the end whenever you see an UFO catcher machine you'd be very tempted to try it out.
Most machines cost between either 100 yen or 200 yen per play. I think I've seen 300 yen per play before but they are pretty rare. If you think about it, it's not very expensive, but if you keep going to game centers, sooner or later your wallet will suffer.
Plushies, figures, figurines, keychains, wallets, takoyaki maker (I've gotten it once for 300 yen from an UFO catcher), snacks, cute utensils, blankets, and even ice cream.
UFO Catcher machines normally takes about 1/6 to 1/3 of the total space in a game center, and if the game center has multiple floors (which is normally the case), the first two floors are probably designated for UFO catchers.
On higher floors, you might see the Medal Games section, which is pretty much slot games and pachinko games. I've never tried any of the machines because I can't stand the smell of cigarette smoke. Usually you'd have to buy medals or coins before you can play those games.
Sometimes you'd also see Rhythm Games section. Rhythm games refer to something like Guitar Hero, but Guitar Hero seems to be unpopular in Japan. Rhythm game machines here are very advanced, starting from something simple like the Project Diva Arcade (4 buttons) to something more advanced like ReflectBeat (touch screen), BeatMania DX II (DJ-like equipment), JukeBeat (4x4 panels), Taiko no Tatsujin (Japanese drum), Dance Dance Revolution (4-panel steps), and Dance Evolution Arcade.
Basically, if you've played Dance Masters in Kinect, this is the arcade version of it, with very up-to-date songs like AKB 48's Heavy Rotation. No panels required. The bad point about this machine is that it's definitely not designed for noobs because you will look very very bad if you don't know how to move properly. You can score an A by doing the poses shown on the screen at exact timing and it's not that hard, but... you look like a loser. Really. Well I DID LOOK LIKE A LOSER. LOL.
Some other cool games are the GUNDAM Pods. They don't have this in a lot of game centers. I'm sure one of the game centers in Akihabara will have this, but I didn't see this in TAITO Games in Shinjuku and SEGA in Ikebukuro. I found this GUNDAM Pods at Diver-City, Daiba, where Gundam Front Tokyo is. Obviously, the game center there would have this game.
The interiors are pretty cool, just like the ones you see in Gundam anime / manga minus the panels and switches and fancy keyboards. I think I've covered this GUNDAM Pods when in my previous post about Diver-City's Gundam Front Tokyo.
Another cool machine is actually the card-based machine. So far I've seen three types of this card-based machines: football, RPG and war-based games where you have to control groups of army units using cards. Every single movement of the card has a meaning.
If you're interested, perhaps you could google Lord of Vermillion (made by Square-Enix) and I'm sure someone has uploaded a gameplay of it on YouTube.
Game centers are probably a little boring for non-gamers, but at the very least if they like cute stuffs, they could try playing UFO catchers and hope for the miraculous beginner's luck :)