When is 1" mdf or thicker really necessary?

[Dragonsyph]

Ok cool, so really birch or MDF are the options?  Whats easyer to cut?  Guessing birch because MDF is so fucken heavy.

 

Almost to the point of building my box so was just wondering does it really matter?  Just go with the cheapest option?   

Last time the store only had 4x8 sheets, would buying 4x4 sheets at another store make it easyer lol?