Tivo and Directv?

I have a directv hd box and was thinking about going with a simple tivo series two box to go with it. I know it can't record in hd but was wondering if it would work for simple recording of my shows and whatnot. What are some of the problems I may have if any connecting the tivo to my hd box? Is there anything else I should know before I make the purchase? Is it worth it? Any help would be greatly appreciated...