CRAN
I disagree with you.
Sure the 139 is currently an unknown quantity but the other types you mention also have problems.
The EC155 is underperforming (revised version with more power coming out very soon) The S76C+ needs its Arriel 2S1 engines changing at regular intervals and the Bell 412 is such a backward leap in technology (even in EP form) that it is costly to maintain unless you are flying very few hours.
LE