My son is 3 1/2. He LOVES his kindle fire; and I like that it doesn't require a data plan and has a very secure child lock on purchases. So I found it to be cheaper on the whole and just as effective. Plus it's super sturdy, and the weight has not been an issue at all.

I would most certainly recommend the iPAD for kiddos with Autism over anything out right now. It is so well worth it. I do recommend getting an indestructible cover for it. My son WILL throw it if he gets frustrated without a blink of an eye. I also have to say that if you can afford it I would get 2 because you'll want to use it too.

Don't forget to consider weight in your decision. If you are considering iPad mini, that's very light (0.68 pound), but iPad is not very light for a three-year-old (1.44 pounds). But iPad mini has a smaller, less sharp display.

I don't mean to confuse you Ruby, but definitely consider Nexus 7. It's Google's tablet, it's as cheap as Kindle, nearly as light as iPad mini (0.75 pounds). It has a very clear display. Plus, it is android, which means more free apps.
http://www.google.com/nexus/7/

Overall, I recommend you not to buy the iPad. I think it's not worth the extra money. I can say that there is nothing your little girl can do on iPad that she can't do on the other two tablets.

The otter box case is indestructible! Highly recommend it, get it on amazon.

This is really a matter of personal preference and what a parent can afford. I have an Ipad, a 7in. Acer Android tablet, and a Fire. I am planning on upgrading my son's older iPad to an iPad mini for his birthday. The only reason he will be staying with the apple family iPad products is because we already have a lot of apps, music, and movies for that platform. Android tablets come with lower prices, you can find models with expandable memory, and there are loads of educational apps.

There are a few apps made only for iPad but you will always be able to find comparable apps on an android platform. The exception seems to be Disney. They seem to be firmly committed to Apple.

Parents should see if their friends would let them spend a few minutes exploring their tablets to see which ones they think would be best for their wallet and their child.