IAH compared to sfo and ord is apples to oranges. United doesn't allow the parking break to bedroooed signaling an out tjme until the aircraft is ready to move and in oRd that means the aircrsft has been deiced at the gate and ready to push. Having been based in IAh for quite a few years i can say our Crj operation out of there was amazing, ground crews were ok but never a weather issue. The delays skywesy has in ord on the 175 is mostly catering, fueling and deice.