I actually started off with Mou, but I've found Haroo to work a bit better for my needs. It's got better shortcuts (although I don't need them) the interface is a bit nicer and it's got more customization. Plus since Haroo is built using node-webkit, it runs cross platform.
Much the same, here. For some reason the font rendering on my Ubuntu machine seems sub-par (only in the editor, the preview pane looks good). The Windows and Mac versions don't have that problem.
