In regard to OP's requirement, Hassy may not bring any significant advantage compare to RZ except the name and the looks of Hassy
Size/weight is the main place. Lens quality is comparable, although the extra negative on the RZ is valuable if you need it. RZ is also better suited for close-up work due to the bellows, and has a better cost-to-performance ratio to be sure.
Obviously, if you are travelling with a bunch of lenses the advantage will partially disappear, but a Hasselblad is way easier to fit in a bag than a RZ/RB.
A Hasselblad with 80mm planar is 3.4 lbs, vs the 5.4 lbs of an RZ with the 110mm. Bigger than the weight difference, I think the size and bulk of the cameras make the RZ/RB very difficult to travel with unless you are using a car.
time4d, I do not think you will regret a Hasselblad if you get one- I rarely use any other film camera, other than a little compact 35mm from time to time. Don't expect it to out perform your RZ, though. A lot of people come from 35mm and are probably overly blown away by the results from a Hasselblad. They can be had for reasonable prices if you are patient-- although I have to admit, if I were to do it again I might go the Bronica route and sink the excess money into large format stuff. I've been waiting for a reasonably priced 100mm 3.5 for some time, whereas I could go grab the probably 98% comparable Bronica 100mm 3.5 for <$200. Also, Bronica has 1:1 macro without tubes...
That being said, if you feel lust for the Hasselblad, you'll probably keep feeling it until you try one out. If you buy smart, you can always sell it for little-to-no loss.