If your going to spend the money on a better unit, why not get the GPS also. I've never had GPS on my other units and regreted it later it's actually probably cheaper to buy it now than to add it later. Now I wouldn't dream of fishing with out it. I don't use it everyday but I use it more days than not.
As far as which unit to buy. I suggest you go to a BPS or another store and look at the units you are interested in. Push the buttons and see what visually looks good to you.
Don't worry acbout which unit is easy to operate, they are all easy once you get used to them. Sure some may take a little more time but they all have a learning curve.
Then get on line and look up BBG Marine and talk to Brian. He's very knowlegable and his prices and service are very good. You won't regret talking to him.
He's on this site so you can send him a pm also.
PS Lowrance has some pretty good reates going on till Feb I think.