Hey Bud,
This is strictly my opinion, But I was looking at about the same thing you are "I was on a budget", I wanted good quality that I thought would last, I was trying to get a combo unit as well... After talking to the sales guy at SW for a little while "a CFFer " He was telling me he uses a hand held gps with a map card more that his gps on the installed unit " you can carry it to other peoples boat and use it for other things..." I decided to get just a FF and then get a Hand held GPS unit which I can also use for 4wheeling, you can split the price into two purchases which fit my budget better anyway, That opend up a hole new line of FF I could look at...
I found a 510c Lowranc color unit at SW for 380$ on sale which was normally 500$ and have not looked back, great quality factory warenty, you can see the unit on my "cats at the nuke post from 3-20" , now if I can figure out how to read it...emoBang emoBang
Food for thought...good luck
Puddle...emoUSA
PS ,If you still want a combo unit might want to look at the Lowrance 68c "i think" color gps, I dont know anything about the hummingbird...