I like TeXShop. However, I think the syntax highlighting is not as useful as it might be. As it is, TeXShop simply plots blue every space delimited string starting with a backslash, regardless of whether the string is a valid commandsequence or not. This contrasts the functionality of integrated development environments for programming like Codewarrior and Xcode which only colourise commands and variables that are defined at some level of a project. This is really functional for it reinforces you when you type in a genuine function name and, reversely, warns for typing errors when the function or variable remain black. Apparently, these program maintain a database of defined names. It would be nice to see if similar functionality could be accomplished in TeXShop.