My suggestion is to purchase the biggest unit that you can comfortably afford. All of them out there have their shinning moments and their downfalls.
I would suggest going to a box store and look at them side by side. I also recommend playing with them. Don't read the instructions or ask for any help. See which one is easier (for you) to figure out without the manual. For me, I cannot figure out one unit to save my life yet the other I have no problems with.
Everyone has their favorite for one reason or another. It comes down to the person making the purchase.
The hook 7 are nice units. Actually a slightly dumbed down version of the original HDS (non touch) models.
I have OCD "Obsessive Crappie Disorder"