According to what I've read, 6-row has more protein and enzymes than 2-row, but beer made from it tastes grainier than from 2-row. One benefit for breweries is that the higher enzyme content allows the use of more adjuncts like rice and corn (both cheaper ingredients than malted barley) that don't have enough enzymes to convert by themselves. The difference in cost is probably not significant for home brewers, but the accountants at the largest breweries rebel at increases of fractions of a cent per barrel given the volume of beer they produce.
Most brewers think that 2-row malts have a fuller, maltier flavor than 6-row.
6-row malts are only grown in N. America and mostly used here. European marketers use this fact by saying their beer is better because it doesn't contain 6-row.
That said, the great thing about home brewing is that you can brew what you want to drink without having to please accountants, or to whatever the latest fad dictates.
Don't be afraid to ask questions. That's how we learn.