\_ Signals travelling through DSUB cables experience a higher signal
\_ deterioration. Now why exactly, due to worse shielding or whatever,
\_ I'm not sure.

That's mighty curious since they presumably start from the same video
out source/pin configuration, no?  Perhaps you have a
faulty/inexpensive cable for DSUB and good/pricier one for BNC?

\_ [..]
\_ Btw... if you go BNC, get a screen where you can easily switch the
\_ input source (like through a menu select). BNC or DSUB. Very
\_ convenient. On my Philips 201P I have to walk around my desk to do
\_ that.

I knew there was a reason I liked that iiyama...an LCD menu on the
front with the obligatory three button control set.  If you leave it
in the right setting, a single press will pop the input select.  :-)

David