My box for my 3 10" type-S's have seperate airspaces for each sub meaning that there is MDF seperating each sub from one another. I was wondering what the difference between running it like that and sharing one big airspace for all 3 subs would be.

Basically a separator is there to "protect" the subs.
Say you have a 3 cube box, because you needed 1 cube for each sub. Say you go stupid with volume control and one sub blows, now you have 2 subs in 3 cubes, 1.5 each.
The effect of increasing the box size for the sub is decreased powerhandling by the means of overexcursion.
It's not that it's necessarily going to happen, but there is a chance once you are blasting them.

It's a good pre-cautionary idea.

That's all I have.

I'm fairly sure if you try searching here, you'll find older discussions regarding this.

df.dima has a good point... and dividers also add integrity to the box.....

As far as SQ, for the most part it dosen't matter.... but from a purist stand point shared air space is the way to go.....the reasoning is that seemly identical subs are rarley really 100% identical.... and mechanical coupling between woofers ensures they are preforming in unison......

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SIC Audio

Agreed. Even though I haven't been able to tell a difference, I still use a single chamber. I used to invert one of my subs also. But it looked strange and took up too much space, so now I just mount both the regular way.

I always like to add bracing though, especially if the box is larger.