I'm looking at upgrading from my original showdown to a new 5.6 dual beam or a fl-18 or possibly the flx-28. I have read dozens of comments on these units. I am perfectly happy with the showdown and catch a ton of fish but, like every fisherman new toys are exciting! So this is what I have in question. I fish a ton of structure weeds, fish cribs, and logs. I currently have problems seeing the fish because of the structure. I don't really get the reasoning for different beams. Nor the difference between the units. Obviously I get the basic stuff. I fish walleye, perch, gills, and crappie so I love the zoom feature. I would like to give vexilar a shot but I have no clue about them. Could anyone help and tell the difference in all these units? I hate to buy a unit and not have a clue what its cabable of!