I have two Diamond Razor Edge bows. One for my 12 year old with the 30-60 lb limbs, and one for my 8 year old with the 15-30 lb limbs. They both shoot great. They are lightwieght and have a wide range of adjustability. They come as a package deal with the sights, peep, arrow rest and quiver. None of the add ons are great but I'm not sure if you can buy just the bow by itself. My 8 year old is shooting his as is but my 12 year old is hunting with his so I upgraded the sights, peep, and arrow rest. I also put on a string stop, stabilizer and a removeable quiver for certain hunting situations.
I know Mathews also has a bow similar to the Diamond and that bow has gotten good reviews also, I think it's the Mission Craze. Like what the others have said, go and shoot some to get the best fit.