So I like nato symbols and if I have the choice I use them in most cases.
So for Panzer Corps both ways are not the best, because motorised units have different modes. They are in the truck or on foot. In Panzer Corps you are able to see the mode the unit has used, with nato symbols you have a difference between motorised units and those without a truck. Both are important information, so to have both would be great.
Next important point is to differ troops of allied nations, especially infantry. So you have to handle romanian and italian infantry in another way than the german ones. Same is true for americans and british or french ones. They have different combat stats and it is important which unit conquers a flag. So I had some games with romanian city flags in a important position to recruite new troops
So nato symbols are very good to get this information.
Ok nato symbols are not as good to remember units stats, because it is easier to deal with real figures than with names. But there are so many units, so I have to look up the stats in most cases.
I would like to have an in game button to switch between both settings.