Flooring Tile - backerboard vs. cement board??

i am about to lay ceramic tile in my bathroom within the next week or two. i've got it down to the floor boards. i am going to install 1/2" cementboard or backerboard. any advatnages to either?? i've heard use cementboard, then backerboard. is one better than the other?? i would think backerboard would be easier to cut, so i would rather use that. less messy and such... do i need to mud the joints of either once laid?? or go right ahead with tile adhesive??
thanks...

They are two names for the same thing. The three major brands (DUROCK, Wonderboard, and Hardibacker) are CBUs, Cement Backer Units.

thanks for the reply... at the home depot by me, they have the durock brand, i'll probably but this. but they also have something called cementboard. it looks like cement with a mesh inside. sits right next to the durock. it doesn't look as easy to cut or handle. the durock says right on it for floors and walls. so i'll just buy that for both my shower walls and floor...

Not in a shower floor, backer/cementboard needs to be both nailed and thin setted down .Its the nails that would be the problem in a shower.You dont want holes in the liner!! Use mortar in the shower over the liner that is over a slope. Details for installing pan at www.noblecompany.com see Chloraloy