You can't fly from the US to Leipzig (or Dresden) without connecting somewhere. Last month I flew DRS-DUS-JFK on AB, followed by a flight to DCA. I was using AA award miles and was quite satisfied with AB, but UA/LH would offer more options for flights to JFK/EWR via FRA, MUC or possibly ZRH. I've never been to Leipzig, but I think that the airport is comparable to Dresden in size. DRS is attractive, modern, easy to get to and not crowded, but it doesn't offer many flights to choose from.