about the same for humminbird or lowrance. ive found on garmin the best scroll speed setting is the "auto" setting. the computer does a better job than i can set manually. this seems to be the consensus on garmins. when im scanning shallow water banks i set it at 60ft one side only scan. then i turn around and switch it to the other side(left or right). on the 7" screens you will pick up a lot more(bigger) picture. my contrast is set high and brightness set low at 455khz signal, as this setting will let me see cover, beds, etc but will also show fish returns very well. im not caring about how pretty of a scan i can get on the screen, im looking to see if that tree top has fish on it.
bluball pretty much summed it up as far as a trolling motor. ive seen it scan while floating with the current and the scans look pretty good as long as you can keep the boat straight. any quick movement and the scan will smear.
like i said in the other thread, garmins are great entry level units for the money, but if you can get a humminbird near the same price during a end of year sale then its a better deal if you are buying it for side imaging. during the regular season a $999 9" garmin over a $1600 humminbird or lowrance is a better deal. a lot of folks are buying garmins just for the 2d and panoptix, which garmins 2d chirp is still unbeatable.