Last year upgraded from 1870 to 1871 (kept 1870 for backup) and the best update is the A scope on both screens when split, 1870 only very right side. However, accufish fish is not as functional on the 1871 as 1870. First, you can not increase the fish size on the 1871 and most of the time I can not read the number, and the 1870 you can increase to large. Also, the accufish on the 1871 does not separate the fish individually as good as the 1870 e.g. a kokanee school on the 1870 shows 50 or 60 separate numbers between 7-11”. The 1871 does not separate out individual fish and shows the schools of fish 40-50” lumping the fish together. If it were not for the xtra A scope on BL, which shows jig + fish bite so much better on the 1871 , I would probably still be using the 1870. Anybody else have the same experience. Furuno says accufish in both units are the same but my actual experience shows not so? Thanks