Decipher Challenge II

r fsd dl fdn lbsf st htsn htsn s rsf s g m hs htsf s v rpp s r msts ms hs n s bs r htsf s s c bsd gs sf s cn ts x s htsn v sss ndl bsht wsn ts qsn n p syr v stc fsyr v sr fsl n b rtsr hsn sll csdn st ssr hsn sylmr fsn s rsx fsd hc rcsyl l vr ss r ssdn msk wshc hwsr dn ss c d j rps l vr ssf ssr fs htsll sff s k hs

M successfully defeated the first cipher, a simple substitution cipher of a quote by Mark Twain. Above is the new cipher, using a completely different scheme (or does it?). I'd like to see a computer that solves it. However, I don't think you will have too much of a problem with it. The devil is in the details or lack thereof. And the question remains: Who said it?