The 441 and 541 are both great units. Garmin has these in many different configurations, depending on your breadth of travels, there may be other configurations that work for you. For instance, 541 is translated like this: 5=diagonal screen
size, 4=preloaded with US coastal charts
, 1= type of screen
The 526 has a 5" screen, in not loaded with charts
, and has the newer, higher resolution screen that is easier to view in bright sun(if it has an "S" as a suffix it has a sounder built in).
If you opt for a unit that is not loaded with charts, you will have to use a Garmin Vision card, but this card "unlocks" features that are really pretty cool, mainly auto guidance. With this feature you can provide parameters for the unit to follow based on your boat, i.e. height and draft
, and the unit will provide a course!