I currently have a 93 and am just learning to identify crappie with livescope, so take this with a grain of salt. I do want to add a screen to the boat, so that I can leave one on the map so that I can target marked brush piles without swapping screens constantly. My take on the 9" UHD, 10" Ultra, and 12" Ultra is:
93 - lowest resolution and smallest screen, but workable. Only has one networking port, so if you want to link to another unit and run livescope, you will need the Garmin hub (or other brand). Lowest cost.
102/106 - sharpest image of the three. Although the resolution is the same as the 12", it is on a smaller screen so there are more pixels per inch. The screen isn't much bigger than the 9" for the normal cost. However, I think there may be an upcoming sale on them, so I would potentially buy it over the 9" just because I want to network with livescope and it does have a slightly bigger screen.
122/126 - largest screen of the three, with the image being better than the 9" but not as good 10". Is the most expensive of the 3 at more than double the cost of the rumored sale. Screen is approximately 43% larger than the 10" and 76% larger than the 9".
I spoke a lot about screen size, the actual dimensions are:
7" - 6.1 x 3.4 (20.74 sq. in.)
9" - 7.8 x 4.8 (37.44 sq. in.)
10" - 8.5 x 5.4 (45.9 sq. in.)
12" - 10.3 x 6.4 (65.92 sq. in.)
It is not what you do for your children, but what you have taught them to do for themselves, that will make them successful human beings.
–Ann Landers