I liked his look fine but wouldn't have objected if he was blue. I do think the visor would've been cool, just because it wasn't all that common in the movieverse and would have been a nice homage.
Nah, I liked his appearance in DOTM more than ROTF. Less Soundwave-like but it makes him look more crazy and sadistic.
I'm not sure that I like that shade of blue. Scratch that, I don't like like it. Too pastel-ly. EDIT: Particular shades aside, I just looked up a few more pictures of SLSes online, and I gotta say that particular car doesn't look good in anything other than white or silver
I've got no problem with his appearance in DOTM, though I wouldn't have minded if his head looked a little bit more like the one he had in the game: