It is wrong to assume the Safari on a Mac is the same as Safari on iOS (and even iOS on an iPhone and an iPad are not the same). Here are things I have found so far
- Font sizes come out slightly differently (larger on iOS);
- Background images don't always seem to reach the end of divs. Background colours can show through at the edges (either it's own colour to it's parent);
- Phone numbers are treated as links – need to anticipate this in the stylesheet;
- Aligning an image with a background colour can lead to a blurred edge on the div. Possible reason of this is the scaling of the page in the iPad not rendering all things equally.