I have read a couple of other posts that make talk about breaking in the saddle. Is it similar to a good hiking boot that you have to put a couple miles on it before it starts to get comfy? I have past the stage of my butt hurting on my bike but would like to know what to expect if I decide to upgrade the saddle soon.

You can only break in a leather (Brooks) saddle. With plastic saddles you have to break in your butt.

I don't know if that is 100% accurate, I mean, anything will "age" as it is used... But yeah, mostly a plastic saddle is going to stay pretty stable. Leather saddles like a Brooks have a process of breaking in and becoming more comfortable over the first few hundred miles.