I own this game.
If you take it as a tamagochi type of game, it's well done. Cute graphics, lots of options (for a game of that type), it's the perfect game for a handheld. I find it hard to understand that people play in 2h streches, since what you can do is pretty limited, after all. It's better enjoyed in 10-20 minutes sessions, twice a day.
Sadly, I would find it hard to rate it higher than other games of that type. Seaman, for the dreamcast, felt much more complete, and had much more options and things to do. Since the puppies cant die, there is no challenge, of sence of urgency, like in Seaman. No goal. You don't even have to be the top rated dog or anything in the competition, since you dont see other dogs competing
You dont even see their results.
The microphone is pretty meh also. The animations are very repetitive and get boring REAL quickly. It's cute at first, but.. There's also a lot of weird glitches and even some colision problems. Yesterday one of my dog was laying on the floor, the other dog was right next to him, in a half sitting / half standing position with his head looking like it was laying on the back of the first dog, but it looked real weird and lifeless. The dogs didnt even blink too :| Maybe it was just a bug..
It's still a nice tech demo, and it will be very successful, but it gets stale VERY quickly since you can only teach them about 6-7 commands and thats it.
You can collect all sorts of items, but.. do you really care about having 5 different colored frizbees?
The big problem with Nintendogs is the lack of goal. My sister played a lot of the weekend. She went from incredibly hyped about the game, playing non stop, and she hasnt touched the DS sunday morning. Once you've seen all the animations and tricks, there is nothing else to do.
I'm not surprised to read that the american version will have more things to do, since the japanese version gets stale VERY quickly.
I would give this game a 8/10, but giving it a perfect rating is weird and reeks of moneyhats.
Still a very well made title, well done animations.. but not much substance after a while. It's still going to be very popular.
edit: I really liked Seaman when it came out, and finished it twice, and I'm sad to report that the current japanese version of Nintendogs feels like 30% of Seaman.