Models with HT in the model numbers appear to be the Energy Star rated refrigerators that have quiet compressor motors.  We had a FFTR2045V that made a very high pitched loud humming sound whenever the compressor was running that had temperature control issues that we replaced with a FFHT2045V that is a lot quieter and will cost less to run for a few dollars more.  The Energy Guide tag does make a difference, wish we had known that when we bought it but the store only had the cheaper one in stock so we learned a lesson.  Hope this helps otherwise, the two refrigerators are the same in all other regards.