Dilbert - Columbia vs Mill Creek?

[FourEyes]

What's the difference between the Columbia and Mill Creek versions of the Dilbert DVD set? I see that the Mill Creek set has three discs instead of four, but is that due to compression, dual-layer discs, or does the Columbia set have special features that the Mill Creek set lacks?

I'm really hoping that the Mill Creek set is fine because I could pick it up tomorrow at FYE while I'm in the area.