Ok..... I'm looking at getting a mac 11 just to goof off and waste some ammo. I'm fairly new into the class 3 stuff and need some opinions and advice on this weapon. I was able to find one that i liked and do not know if im getting a good deal or even in a mac 11 is worth it? Has anybody ever used these weapons or own one that can give me a few pointers? It is the SWD Mac 11 and Lage Mac 11. Is there any difference in the two?
Mac 11

I believe that SWD 11 is the actually gun and the Lage Max 11 is the aftermarket upper receiver

The lage is  an upper that used on the M11 by SWD, the lage is just and upper. No point in buying a M11 with out a lage. M11 start at $2800 and the lage is about another 700 for the basics.

is a mac 11 worth it? are they decent weapons just for goofing off?

The m11/9 first off is not a MAC. The m11 is definately worth the money with all the options out there, it is basically the ar15 of the c3 world. The Lage upper is the only way to go with one. It really turns the m11 into a match competent subgun. The lage at a minimum starts at 795.00 and a good m11 starts at 3k. When your all done and set up including the cost of the stamp be looking to shell out around 4k for a good setup. The m11 is also usable on its own with a lot of practice.  Check out Max-11.com and Uzitalk.com and ask some ?'s.