it can almost be a chevy vs ford debate. in many cases there is just a lot of brand support simply because it is what someone has used before. and this is a valid argument. if you are accustomed to the menus on a particular brand, then it just makes sense that you will find that unit easier to use than any other.
with only a few manufacturers making quality gps/fishfinder/bottom machines, it certainly is like ford, dodge and chevy--each one is a great quality piece of equipment, within the limitations of the particular model.
i have to remind everyone looking at equipment at BPS or West Marine or wherever you are shopping. please understand an icon of a 'fish' or an 'arc' is absolutely not always a reflector of an actual fish. the units that have cute little fish icons, might better be left for kids to play with. if the unit senses any reflector--could be a fish, could be weeds, could be an odd current or thermocline--any reflector that that is not attached to the bottom, will be displayed as a cute little fish.
and arcs--that can be very 1980's. while there is some validity in the technology and algorithm used to display 'arcs' as true reflectors, technology has advanced in recent years. first, it has to be unattached, and then changes in velocity of the ultrasound will be calculated as a true reflector. the unit then displays it as the tell-tale arc. its math, and software. they could make it look like a smiley face, a duck or a little fish picture. but, for last years technology, it works pretty well.
technology has advanced so far beyond that now. modern DSI units--of each brand, provide images that are near medical quality. it is amazing.
the best advice i can give is to keep using and learning and practicing with your unit, to be able to read the signals accurately. its not easy. ive been teaching it for a decade, mostly to boat owners, and it simply takes practice. no matter what unit you have, it takes practice to learn your way around the menus and setting and learn when to change settings to ensure the data on the screen is as accurate as it can be.
'but i just want a simple unit to show me where the fish are. i dont want all that other crap'. well, when someone makes a unit that is simple enough to just show me where the fish are, i'll be standing in line to buy two of 'em.
with regard to the brands, i certainly have my bias. sorry, but i do. i try not to push my brand, but i will tell you i do love the equipment. while garmin makes great gps technology, they are still a few steps behind in sounder technology. sorry, thats just how it is. if you want a simple unit, just for depth and a few obvious reflectors, its not a bad choice.
as far as the brands other than navico/simrad/lowrance--how many humminbird units have you ever seen on a commercial boat, an offshore boat, a sport fisher, an open ocean sail boat or other high end vessel? it has nothing to do with the size of the display--everyone makes a big display. it has everything to do with the technology in the box. and if that technology is available for my kayak, that's what i want to use.