I have a SD automatic, roof mounted DirecTV antenna. I am totally satisfied with it. To upgrade to a HD automatic antenna was $2000 when I last checked, 2 years ago. What do I get for that amount of money? A better picture on a bunch of channels and half the amount of storage space on my DVR. Because these days I get the local channels (ABC, CBS, NBC, Fox, etc) on my conventional antenna and these channels are often in HD, I am happy. Even it the local channels wern't in HD I'd be happy.
Because you have a SD automatic antenna only you can decide if it is worth $2k to upgrade to HD. I continue to enjoy the extra $2k in my pocket.
Eric, currently outside Ft. Wayne, IN