Let me pitch in as another Rollei 6000 system owner.
There's some untruths in this thread.
Dead batteries?
This is pretty much solved nowadays, you can buy re-built NiMh packs and a charger and they hold for many many of rolls, it's a non issue.
Heavy?
Yes, but the vertically oriented form factor is ergonomically easy to crade and the side grip on the 6008 again makes it easy.
(Bonus, the newer rebuilt battery packs are lighter!)
Plastic?
Yes on the exterior, it's solid metal underneath.
Nobody services them?
There are several places here in Europe who service them, my bodies and lenses where serviced and are fine.
Electronics longevity?
Sure, but there's significant survivor ratio here, all the old first gen SLX' and 6006's with failing electronics are long since dead, checked models are most likely just fine for years to come.
A Hasselblad can just as well lock up on the job at any moment.
....Are there advantages? Yes!
Price: At current Hasselblad prices, the Rollei system is *extremely* competitive,
I paid for my Rollei 6006, Rollei/Zeiss 50/80/150mm, extension tube, 2 backs and 4 inserts less than the current going price for a single lens and back Hasselblad kit.
Speed of use:
Builtin accurate meter *without* needing to use a prism with shutter priority, killer feature.
Instant mirror return and motor drive, this means i do not need to look away from the finder between shots.
All this combined allows me to work fast at people photography.
Accuracy:
Inaccuracy of shutter speeds is already enough of a pain with Copal shutters, electronic shutters that are always accurate is definitely appreciated.
And accurate shutters again help when shooting series, with perfectly consistent exposures darkroom printing all images from a session becomes faster.
Fool proof:
No lockout scenarios (Didn't cock a lens? What order do extension tube and lens go again? yada).
Built in dark slides, nothing to stash away, just push a slider, it's always obvious which state you are in.
....I suppose i shouldn't write these down and just persist that the system is terrible and will die any moment, it'll keep the prices down on any other lenses i might still want :-D