Had a couple pm's w/ questions. First this unit is side imaging and down imaging. Second, if I recall correctly the 1199 is faster than the 1197, it can be used with 360 imaging which 97 can't, and I don't believe you can Ethernet connect the 97's.
The 1199ci HD SI Combo has a faster processor than the 1198 also.
The 1197 is the only XX7 model that is Ethernet compatible.
Humminbird Helix 12 SI, 1198c SI, 1198c SI, ONIX 10 SI NT, 360, RC-1