Well, opinions are like a-holes. Everybody has one. For what it's worth, the Lowrance SI units use three separate transducers to obtain their sidescan and downscan images. The 'bird uses software to derive their downscan images. The Lowrance comes with the Fishing Hot Spots topo maps, but a number of other add-on options are available, including the Navionics high definition maps. I've seen comments on this board that the 'bird is easier to use, but it didn't take me long to come up to speed on my HDS-8.
One of the things I really like about the unit is that you can network your bow and console units, so that if you set a waypoint on one unit, it shows up on the other. The other neat feature is that you can also network all the essential features displayed by your console gauges to display on your Lowrance head unit. Plus you get such neat stuff as fuel level, miles per gallon, gallons per mile, distance til empty. Of course you get an accurate GPS speed reading. My only complaint is the Lowrance has yet to come up with a device that will replace the console tachometer.
Last, but certainly not least, are that the sidescan and downscan images are truly awesome. This technology completely obliterates standard sonar images while fishing.