It took me a long time to be able to read the rest of the dune books , the first generation ones anyways. Dune was a strange book , for some one reading sci/fi for the first time, and being used to Clark, Pohl ,Niven style of writing.
Some of the classics are definitely better read when you have aged a bit ,and been through the world and have some life experience. Some Dune fans took to it as soon as they picked it up , but not me.
The next generation dune series, with Brian and Kevin , would be like someone who has time traveled from the sixties and hit the oughts, all the names are familliar , the places and the genisis for what becomes the guild and the great houses, but its written so much different that it should be more rated on its own ,than on anything Frank Hebert wrote ,but there is as much chance as a snow ball in hell of that happening.
The most you can do is read both , the original from either the library or used book stores , and then the new series , if you get it , you will either like it or not.
However I do think that most original dune fans are pre-conditioned to not like the new stuff , from stuff I have read on the net.