I usually post from Firefox on my PC but I was working on the Mac today and decided I'd post from the Mac. Unfortunately, I was in for an annoying surprise when I attempted to use Safari to post.
The screenshot above (click on it to see a bigger, easier to read version) is what the screen looks like when I use Safari. If you look at the toolbar across the top (just under the "Title" box), you can see there are only two icons. From Safari, the only thing you can do is spellcheck or add a picture.
The screenshot above is from Firefox on the PC and, as you can see, there's an entire row of options when posting including font type, size, style and color, linking, paragraph alignment, list formatting, spellchecking, picture addition, and format erasing.
I'm not sure if the absence of these options on Safari is because of Apple's coding of Safari or if it's related to Blogger not supporting the Mac's default browser. Either way, it's yet another reason to use Firefox.