Concerts--especially rock shows
with a lot of lighting changes--can be among the trickiest subjects to shoot. Look for a camera that offers spot metering, high ISO settings, slow-sync flash, and a manual focus ring on the lens. A lens with a wide maximum aperture and a big zoom range will offer better low-light performance and help you adapt to the space you're shooting in.
A digital SLR
generally gives you cleaner images in low light than a point-and-shoot would, although the loud click it makes when you take a shot isn't ideal for quieter musical events. If shooting soundlessly is a priority, an EVF camera is a better option, but make sure that the LCD and the EVF on the model you choose don't become unusable in low light.
Getting the color balance right when you're shooting a concert with stage lighting can be difficult; I recommend you use a camera that shoots RAW files and adjust the white balance with RAW-processing software afterward.
Not all concert venues and performers will let you in the door with a camera, so check the policy for the event you're planning to shoot in advance.