This is one of the absolute best models of Mecha Sonic I've ever seen. Pieces of art, even. This guy is rare as hell, and absolutely awesome. Personally, I reckon he's a bit more intimidating than Metal Sonic too, who is just downright adorable.
Very nice! I like the shiny metal and the colors are great (a nice green to blue) so it looks like the glow of the emerald is coming from below...I wish I could comment more on its construction but since I know squat about 3ds Max...I can only give my opinion that it really looks true to model based on the 2d pixel version like if it were upgraded to a 3d version of the game, this is what I'd like to see happen.
I'm glad you mentioned that it looks true to the original sprites, because I definitely put a fair amount of effort into that. I'm used to being lax with my interpretations and just shrugging off inaccuracies to the style. This model was a good test at sticking close to the source material.