I bought this buggy for my son last year. It's suitable for ages 8 and above (he's 12). It's a really good buggy good overall features for a kid's vehicle, decent charging time, and good speed. I wrote a full review about it that you can read here:
http://www.gokartscentral.com/razor-dune-buggy/
Pros: Everything mentioned above, and it was affordable for us.
Cons: It doesn't go in reverse, which many children need. It also lasts for just 40 minutes.
My rating: 4.5 out of 5.