Older GPS prefrence???

[Boatmon]

I have a question for all of you tech type guys;

but first a little history;
When we purchased our Albin 36 Classic it had a Garmin 182C aboard, the unit is fairly new and works fine, but the Unit we are most familiar with is the Standard Horizon CP 150C. The fellow that purchased our old boat may be willing to trade our old Standard for the Garmin that was aboard. Either way I am going to need to buy a new unit for the lower helm area, and one of the two units would be located on the bridge dash. We know the Standard and also have the Lake Michigan and North Channel (our cruising grounds) c-map with it. The Garmin Has a South Florida Blue chart in it (of no use to us) My thought is that if we put the Standard on the bridge and buy either the CP180 or the CP300 (by Standard)for the lower helm, then the C-map card will be able to be used in either unit

So my question is, do any of you have experience with either or both of the older units, and what are your likes/dislikes?? And does my logic make sense?

Any thoughts and input would be greatly appreciated.......