Forgive this rather lengthy reply, but want to cover a number of issues. I started with Rollei back some 30 years ago with a 60063 and 80/2.8 lens. Used it all the time, travelled with it. Had the advantage that the back was slim (no dark slide), handle could come off, and without the prism, it was only somewhat heavier than a TLR, but not quite the beast you might think. Workable. And the images were wonderful. Never a problem with it.
Over the years, got more lenses (many, many) and found some nicer, slightly off the radar ones to be optimal: really liked the 60mm Curtagon (build a system around that lens), the 150 Tele Xenar (much smaller than the 180), and the 250 Sonnar (much smaller than the 300 Apo, but as good at f11. Didn't care for some of the more exotics - the 55PC, the 90 is superb, but too big for my use, short DOF; the 110 superb, but again too heavy. The 180 is nice but also heavy, recommend the manual focus as the AF can go wonky and is not repairable (at least very very hard). The 40mm Schneider was great, a wee bit soft on the edges, but still superb. Not quite as good as tech camera lenses, but fast and small....
The 45º prism is a treat, often made the cut for traveling. Over time, upgraded to a 6008AF (didn't really care for it - trying too hard to be something it wasn't meant to be, and the batteries didn't last); ended up with Hy6 and digital back. Super combination, worked well for about 10 years with this. Focus confirmation with MF lenses was superb, no need for AF. Totally in the fold for a long long time.
So why no longer? A couple of reasons - the support from Germany worked well for many years, was fast and effective, but it got a bit spotty. And then there is the fact that the camera is designed to cover 6x6 with these large lenses (which are lovely, BTW), but the form factor was just too awkward for travel. If the Hy6 handle would come off, would be much better. It just seemed the world moved on to smaller, more integrated, less fussy. Wanted to get a more modern digital back on the camera (for higher ISO), not possible then. (There is a guy in China working on this). Didn't like the closed system getting harder to service ( an understatement....). But every day still miss the Rollei. It could do anything.
Recommendations: the 6003/8 are superb. Keep an eye on the lens package - smaller is better. There are exotics, and they are neat, but the weight gets up there fast. Stay with MF if possible, more rugged. AF lenses will need attention at some time, and parts are harder. The 80 2.8 is an exception. Still, the 60mm Curtagon is exceptional, luckily found as good in the Schneider 60mm XL for tech cameras.
Hope this is helpful.