The real benefit of RFs optics is that they are SMALL lenses. A ZM biogon 25 is tiny compared to the ZF equivalent and performs as well or possibly better if you believe some, including the odd poster who has both.
If you want to hike all over the place, shoot at slow shutter speeds etc, which can be handy for landscape work too, then a RF will give you superb optics and small size etc. You can even hike with a little tripod over your shoulder (or not at all) and the kit in belt pouches. I cannot comment comparatively, but my ZM wides, 50 planar and 90 Elmarit M are not bettered by anything I own in 35mm, but not better than my 135 f2L either. The consensus seems to be that at the wide end, RF lenses have an edge due to more flexibility in design due to the absence of a mirror. If it is really noticeable with other factors, who knows? I dont. I only know that the ZM images are tack sharp and really made me feel that I was getting everything out of the tiny 35mm format. no doubt about it, the Mamiya 7 makes mincemeat out of the ZM 35mm shots, but that is not your question, but the posters who suggest the 120 route do have a point: unless there is a reason you must stick with 35mm, a Mamiya 7, esp for mono, where grads etc are not required), offers a HUGE step up in quality than renders the RF vs. SLR argument irrelevant. But, personally, If I was to choose a landscape kit from 35mm, I would go RF every single time. Smaller, lighter, easily as good, smaller filter sizes, also great for street work, optically wonderful. BUT, I dont do macro work, portraits etc. one point I would make is that ZM lenses offer staggering edge performance and when enlarging 35mm to the extremes, this is noticeable. An earlier point was well made though, which is that when stopping down to f16 etc, most lenses perform bloody well, even cheap ones (except for cheap nasty zooms).
