Is God's system evil?

I've written many times abut my surprise at realizing that the Bible tells us that while all are saved by grace and can go to Heaven, once we get there our rewards in Heaven are based on our works.  Here is probably the single most clear passage on the subject because it is Jesus saying it. 

Revelation 22:12-13(NKJV)

12“And behold, I am coming quickly, and My reward is with Me, to give to every one according to his work. 

13I am the Alpha and the Omega, the £Beginning and the End, the First and the Last.”

Here is what I don't get about Red Letter Christians (Christians who believe that socialism is Biblical).  If as Jesus says our reward in Heaven will be based on our work, why would you not expect it to be that way on earth as well?  And if reward based on work is the system established in Heaven by God then why do Red Letter Christians call that evil here on earth?  Is it their contention that the system established by God in Heaven is evil? 

Just wondering?