Wow! Toon World! Sounds like fun! In the Comics, Pegasus uses this card to defeat Seto Kaiba, and even give Yugi a run for his money. In the comic, it has extraordinary powers. In the card game, it has the amazing ability to suck.
First off, I'd like to tell you that this card has been errataed! The translation at the right is the same as on the Toon World from the Pegasus Structure Deck. However, the actually Pharoah's Servant card requires you to pay 500 Life Points every Standby Phase to keep the card in play. When the card is destroyed, you regain all of the life that you payed to it during your Standby Phase. When the card comes out in America, who knows which version they'll use. However, if you read on, you'll discover great reasons to not care.
This card allows you to play Toon Monsters, and must remain in play. If Toon World dies, so do all of your Toons. Toon monsters' abilities may vary, but for the most part, they can't attack on the turn you summon them, can attack the opponent directly if your opponent has no Toons, must attack Toons if there are any on your opponent's field, and require you to pay 500 LP to attack with them.
Those are just the basic abilities of most of the Toons. The ones in Pharoah's Servant have another ability: They count as special summons. However, they're a weird kind of special summon. For example, a Level 5 Toon Demon counts as a special summon, but still requires a sacrifice of one monster to be played. It's kind of like having Blood Offering in play, where you can summon as many monsters as you want per turn. Still, this counts as a special summon, and it's important to remember that.
So, what do we have so far? We have a card that requires you to pay 1000 Life initially just to play it. Also, Toon monsters tend to deal you 500 damage when they attack, meaning that you'll be taking a lot of damage while using Toons. This makes them very risky. Also, add to that the fact that they have to wait a turn to attack, and Toons become risky and slow. Add to that the fact that Toons will be destroyed if your Toon World is destroyed, and your Toons become risky, slow, and easy-to-kill, because all I have to do is use Harpie's Feather Sweep, Heavy Storm, or Cyclone to kill EVERY Toon Monster you have. This approximately doubles the amount of ways that you can kill Toon Monsters, and is in fact more effective than killing them individually.
Also, Toon Monsters can't be special summoned from the Graveyard unless they hit play first. That means that if you discard a Toon from your hand, you'll never see it again.
In the American game, I can see why you might be tempted to play Toons, but in the Japanese game, there's absolutely no reason to. If you want to deal large amounts of damage directly, there are plenty of cards that are moderately-sized to do the job. Combo them with cards like MR-02: Demon's Axe or SM-19: Mask of Atrocities and you have a big monster that can attack directly the turn it comes into play. Also, this monster won't die if it's equip magic is destroyed, and it won't require you to pay any life. Simply said, there's no reason to play Toons in an organized environment.
Well, that's it. I hope that this has helped to shed some light on the rare and wonderful Toon World.