I haven't heard much about that kit, if anything - I too am moving into a house with a brand new garage and I am not planning on skipping the etching step when/if I put epoxy down on the floors.
I have also heard that you should wait 4 mos (120 days) or so before putting down the epoxy, to allow the concrete to cure 100% - but I spoke to the builder today and he said that would not be necessary...
Alex