Not the GP, but I often just use commas and parenthetical asides (like this).
It's a different stylistic choice (em dashes are nice and all), but it's not how I think, and my writing reflects how I think.
I also will often use the fabled semicolon. It's easy to use with contrasting statements, but that's not its only use; I can use them in some situations to elaborate where em dashes are used.
I'm not saying they are a perfect replacement for em dashes (again, em dashes are cool), but it's just always been my personal style.
I regularly use the semicolon, especially in a sentence where this are commas use in another way. In my mind, a semicolon is a "greater" separator than a comma; used to separate parts of thought in the same sentence (vs grouping of items or a pause).
