I believe the RoboReptile is the newwer of the two. It's supposedly faster and more aggressive, among other things. Personally, after reading up on them both, we ended up choosing the RoboRaptor to give my nephew for christmas. Partly because it was easily available for cheaper, partly because it had the better look (IMO), and mostly because the Reptile just seemed a little too aggressive for our tastes (the Raptor seems more playful).

In all, it's just a personal decision. Hit youtube for videos of both and see which one's personality you like better. 

Watch out, don't step in the anthropomorphization.

I have to agree with the consensus here. I have both and the Roboreptile (mine's a Robotyrranus) is way more aggressive and active than the Raptor. In fact, the person I bought Robotyrannus off was selling it because it still scared their child!!

I started with 2 robots but before I knew it, well, it's a disease I tell you.
RSV1, RSV2, RS Media, Homersapien, Spidersapien, Roboraptor, Robotyrannus and Roboquad