if you're comparing backcombed (which is, according to anything i've read, considered to be under the catergory of natural) and a dread perm, no, not really. the perm tightens faster, i believe. its just a matter in whether or not you wish to put chemicals in your hair (perm crap). of course, completely natural dreads (the bed-head method, that is) look different.. but thats cause they develop way differently. and tend to be of more various sizes and such.
If your going the natural way. Make sure you palm roll often because you going to be stuck with kinked dreadlocks and they are a pain to straiten. Still trying to figure that out...