Bill over the past few years I have gone from a hand held Garmin and black/white ff to a dash mount portable Garmin 176 b/w with a garmin b/w ff to a color combo Garmin 178c,and I have gone with a new combo unit this year but now a Raymarine C70 with radar/ff/gps. I have never had any of the units I have owned go bad and do not know of anyone with a combo unit that has gone bad. This does not mean it can't happen but then agian any unit can go bad combo or not. With me I like the combo unit much better than a stand alone as in a smaller boat (21') it keeps everything handy and neat. But I will say that I have a hand held gps onboard plus the combo unit so if it should go down I will still have the gps to get home at night or in a fog. This year I will have the C70 and the Garmin 178c side by side and the hand held so if one or the other dies I should still have a working unit. Plus if all else fails as in NO POWER and all units are down there is always the good old compass you guys do remember those don't you?
Bill also I would go with COLOR trust me there is a differance a big one. Take a look around I bet you can find a good deal on a Garmin combo color that is discontinued my 178c is and I would buy one agian if need be and the price is way down now. If you would like to see what a b/w looks like next to a color unit come on down and I will hook them up side by side so you can see. Better yet if you can wait a month I could take you and Slip fishing for a night to my spring hot spot and then you can make a on hand judgement.