US Shuttle serves a nice little snack on weekdays. It consists of cheese, crackers, and a couple of other things. Pretzels are served on weekends. However, the DL shuttle's snack is more substantial. But in the end, it comes down to which one costs less, which one fits better in your FF accounts (US gives you 1000 on US, 1000 on AA roundtrip, DL only gives you 1000 on DL or UA) and which jet you prefer flying on. US has newer jets on the shuttle, with laptop power on all flights between LGA and BOS/DCA.