In general, the RAW and JPEG will look different: depending what settings your camera has and how you set it, the color, density, contrast and several other variables (and compression) will be adjusted in the JPEG, whereas the RAW will be completely or almost completely unadjusted. The camera manufacturer is leaving it up to you to adjust the RAW the way you like it.

I've found that about 9 out of 10 times the JPEG will look better right out of the camera, since the manufacturers have done a lot of work in optimizing the image to look good in the JPEG version. But I still shoot RAW + JPEG, because having the RAW is good insurance in case the contrast is too high and I need to adjust things. I end up choosing and editing the RAW about 1 out of 3 times, simply because I think I can do a better job overall (not sure that's really the case, but anyway...)