Looks are a whole different arena smile But from a durability or strength standpoint there isn't a real difference for this application. Obviously a poorly finished piece is reflected in cost. To simply reject an upper or lower because of method of manufacture is foolish. Now if it's poorly finished, over or under size etc. reject it. the two hardest alloys- those used for structural component forgings and castings in aviation 6061 and 7075 are great alloys with substantial abrasion resistance over 1100 or 2024. Though 2024 is used extensively in aircraft- usually skin and stamped former/stringers. Not aware that anyone uses 2024 for uppers or lowers though.