Just got back from the US flying with Delta, and they were terrible. Can't comment on travelling with a bike, but avoid like the plague if you're travelling with a baby. Just a single bassinet on a 767 and no two representatives gave the same answer on how you get it allocated to you. On the way back, we had the only baby on the flight and still didn't get it.
Beyond that, staff were generally unhelpful and in some cases rude, and in four flights we had pilots turning up late, broken a/c, entertainment on two flights broken, and a 1.5 hour delay on the tarmac for a 40 min flight with hardly any explanation.
Total contrast to flying with the sprog on Virgin who couldn't have been more helpful.