Thanks for the feedback. anGy - did have a chance compare the 150LS & 150D? I don't LS lenses, but I do prefer their smoother shutter operation for handheld shooting.
Yes I did compare them in controlled conditions.
IMO they have strictly the same center resolution (did not compare corners) from f4 and faster. At f3,5 the Mam is a little bit sharper.
Contrast & color rendition are on par too.
The Schneider suffers CA (clearly present on metal reflections in my test shots). Same CA was only visible @f2,8 with the Mam. But who still cares with CA, they're gone in one clic with C1...
Bokeh is almost the same but I find the one from Schneider a bit better/softer at comparable apertures. But the Mam @f2,8 is softer than the LS @f3,5.
A big drawback of the Schneider is the minimal focussing distance (150cm instead of 100 for the Mam).
The lens ergonomics I find nicer on the Schneider that has also better esthetic (very personal, I know). The metal sunshade is very nice and efficient (did shot both lenses in flare conditions and both give higher contrast with the metal lens hood). It fits the Mam perfectly and can be purchased separately (350eur excl. taxes in my country...)
As former Hasselblad user I did encounter several problems with LS lenses (1 shutter blocked - 1 AF blocked) and the only LS lens I have now (80 LS) felt (not that hard) on the ground with no apparent damage but AF is out.
Never had any problem with normal lenses (Nikon - Mamiya) and I believe they are more reliable when used out of a studio.
I also like the soft central shutter of LS lenses but - if I did understand it well - the focal plane shutter is not bypassed when using LS lenses so there is no advantage on vibrations alterations.
If the higher synchro flash is not needed I really don't see any relevant point that justifies the Schneider expense. (Yes it is lighter and clearly shorter). Even with the extra cost of the purchase of the metal lens hood, the Mam is still 1000eur cheaper in Belgium.
I did sometimes spend extra cash when buying in the past - just to be sure to get the best - but I got wiser !
rem: tested on an IQ180