Wikipedia has a comparison chart of the various boxes out on the market.

 I recently picked up to Insignia boxes at Best Buy.  From what I've read, they are internally identical to the Zenith - both manufactured by LG.  The Insignia boxes work well for me using standard set-top rabbit ears, but note that I'm within 12 miles of of the broadcast towers in town.

 AntennaWeb.org can provide you with information on distance and heading of broadcast towers in your area.

 Hope this helps.

 Fritz