Again, it's slightly different, most of the samples in Reason are multi-samples designed to be used as musical instruments acroos keyboards, there are loops, especially in the loop player, GB's samples are mainly loops that are dynamically stretched and pitched.
GB also has som EXS style mulit-samples in the MIDI instruments, which is where the cross-over occours.
Of the two apps, Reason will probably be more use for your kind of music, but GB can be very useful here too. I haven't tried to import sample either way, but GB samples are .aif format, as are reasons, so I see no reason (ho ho) why you shouldn't use GB samples in the Reason sampler, and the other way around.