So far I'm very pleased with this product. My 6 year old loves it and wants to play all the time--that alone is worth the money, regardless of the durability. And durability is why I give it 4 stars--I've read the reviews and am less than hopeful on its longetivity. However, when I first got it out of the box, I had the same problem as many reviewers--it came on but wouldn't work. When I opened the battery compartment I saw that the batteries were slightly buckled, I replaced them flat and voila, the MathShark worked. It seems like the battery compartment is just the tiniest bit too small for the batteries; if you're having a problem, try repositioning them. The screen is small and not that easy to read, but it doesn't seem to bother my child at all. It's basically like reading a calculator.