Generally, most digital cameras in raw mode won't have much headroom before clipping. Since the visible effects of over-blowing are so noxious (e.g. grey areas on foreheads or cheeks), with DSLRs that have good shadow noise performance it pays to usually apply a little negative EV Comp.
Some manufacturers choose a lower metering level (see
* below), which can allow more headroom, at the expense of a little more noise in the shadows. Also, if you shoot in JPEG you are applying a Tone Response Curve, and these TRCs often have a bend near the top that makes the camera appear to tolerate very bright situations better.
* Note: "K" is the reflected-light meter calibration constant. Each manufacturer has some latitude in deciding what K value they'll use in setting their metering level for what they consider a correct exposure. K=11.4 was originally used; nowadays K=12.5 (Canon, Nikon, Sekonic) and 14 (Pentax). Higher K numbers mean that exposure levels are slightly greater today, because the brightness is higher. The increase is 0.13 stops ( K=12.5) and 0.3 stops (K=14). Interestingly, Pentax light metering uses a K which is outside the ISO 2720:1974 standard recommended range for K of 10.6-13.4.
Dan.