I'd like to make it clear: this game is one of my all-time favorites as well as my 2nd favorite N64 game. This game is fun, hilarious, clever, and an amazing experience. What started out as a kid-friendly, cutesy game ended up as a crude and lewd game, and it worked great for this game. Unfortunately, due to being released at the end of the Nintendo 64's lifespan (and a high price tag as well) it sold poorly and didn't get the respect it deserved. This reason is why it's great that this got a re-release.
Rare certainly did one thing right with this remake. They updated the graphics very well. The game looks beautiful, and is one of the best-looking games on the Xbox. However, they made a fatal error when porting this game. They censored it. This kind of pisses me off. The argument that Nintendo is a kiddie company compared to Micosoft could fall flat when considering this. It's not that the game isn't fun without the profanity, but it's just not the same. Also, the great multiplayer from the original is replaced with a not-so-good one. This is unfortunate, as online multiplayer could have been great, but instead it's quite mediocre.
Overall, if you haven't played the original, you should pick this up. It has the same awesome gameplay and humor that made this game so fun in the first place. However, this is the inferior version of the game. If you still have your N64, get the original cartridge. While it's a bit on the pricey side, it'll be worth your money.
On the topic of age-appropriateness, this is not a good choice for young children. However, I think older kids and teens, if they're mature, can handle this game.