To me the main things to have are 1: ability to use either positive or negative shift (programable). 2: multiple memory, i.e. the ability to store the trim servo direction on several planes 3: good fit in my hands (there is quite a difference in the feel between different brands) 4: reliability and service for those unforseen problems such as a dropped and broken switch etc. whether they be user induced or age induced. If your choice meets your requirements in these areas, jump in.