I work single coverage occasionally. Sometimes you will get slammed and have to dig yourself out. If you have a critical patient the rest of the ER slows to a halt. Sometimes you can actually empty out the ED. Personally, I don't like it but it forces you to practice real medicine.
Where I work at a large academic center I can rely on my residents, get consults from any service, or admit to any service. It's a great working environment (at least for me) and good for patient care but it can make you soft.