The 2010c has various display options including a selection of detail from none to too much. It also has a hide/show data function. Check to ensure that you have selected "show data" and that the detail level is set at a reasonable level.
The 2006c/2010c/2012c units are very robust and you shouldn't have much difficulty. If you can find one of the old style data card readers on eBay or the like you can update to chip with a BlueChart disc current through 2008 although you will have to pay Garmin for the unlock codes for the areas you would like to have. You can still find Garmin pre-programed chips, which do not need an unlock code, but they are fairly dated by now and must be used with caution. Unfortunately, Garmin discontinues support for their devices relatively quickly to force repurchases which I will no longer do.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."