Yeah, to me it looks more like a futuristic car than an alien one. It wouldn't surprise me if cars will really look like that in 50 years. Part of me wishes the text on the doors we're in English than in Cybertronian.
It's a pretty good modern interpretation of Prowl, and the basic gist of the transformation is similar to the G1 toy - particularly the way the waist rotates during transformation, the back bumper forming the feet, the placement of the doors in robot and alt-mode, etc.
EDIT: I've been transforming the figure back and forth this evening while watching video reviews of it. Not so much because I like the transformation, but mainly to check if I'm doing it right. When getting it into car mode, I can't seem to get the doors aligned so that the pegs plug easily into their respective holes. To get them to align, I had to resort to using force and squeezing the figure. I don't know if it's me or if there's a flaw in my copy. I've tried imitating several video reviewers when transforming it, but kept getting the same results. So far I've not noticed any stress marks or cracks, but I'm not going to further risk it (considering I paid $34 for it), and I've decided that Siege Prowl will remain in robot mode for the rest of its existence.
It looks amazing in both modes, but it does feel rather fragile considering that his legs between the knees and feet are sculpted entirely out of clear plastic.