There are negatives because some people have a hard time whenever apple decides to sell there products with retailers who never sold those products before. It's like anal sex. Rough at first, but gets better after awhile.
Apples brand image is elitist. The BMW to the Toyota, if you like your automobile comparisons. Maintenance of said brand image is important to help maintain the desirability of the product.
Something to strive for. The competitively priced entry product, aka iPad, is important to Apple, as the 1series is important to BMW. It may not be the biggest margin, but hooks people onto the apple bandwagon to help ensure consistent purcahing as they move up the income chain.
To maintain the brand image, while maintaining hte mammoth income, they need to balance availablity of the ipad with 'who' is selling them. Is Toysrus going to increase availability? - probably not as apple iselling as much as it can make
So is Toysrus going to improve the brands image. Associating with a crap reseller may be great for Acer et al, but this is Apple.