Apart from handmade steel frames I understand most frames are made in Taiwan or the RPC these days. Most have large obvious welds which may seem ugly to some but should be stronger than theybwould be with the same weld filed down smooth. I have a 94 Cannondale which has no apparent welds at all but it alleges on a frame sticker it was made in the USA.. Being a Luddite I prefer steel frames but the two Al frames I have work well. Something I have heard a lot about is ride quality with steel being more lively,supple etc. And yet the the part of a bike that is subject to the most flex would seem to me to be handlebars but Al bars have been the norm for 50 years at least.