I know they can be brilliant but I read that with large negatives they don't do much better than a good flatbed.
These are a bit of a strange thing... not quite a drum scanner, as good as a good film scanner on 35mm, great on 120, not much better than a flatbed on 4x5 to 8x10...
Personally, I'm quite sitting in between chairs on voicing an opinion about it. On one hand, I know it's made by Hasselblad and that they don't make junk. But on the other hand I wonder if the rental price will give you that much more in a scan.
At around 31$ an hour, I think you might just end up a bit disappointed by its results.