Hi Stello,
as an allrounder in my opinion the BK 117 is the best EMS Helicopter. It has a relatively large cabin, small dimensions to land in confined areas, can be loaded easily, has good power (hoisting), 2 engines, excellent manouverbility.
The EC 145 is the new version of the BK117. It has a larger cabin and modern avionic (glasscockpit, autopilot optional and so on)
But its heavier, so a disadvantage there.
I guess it all depents on where and for what you need it.
It makes quiet a difference if you do rescue in the swiss alps or in netherlands, or if you just do interhospital transfers or primarly on sceene missions.
The Bell 412 is an excellent transport helicopter because if its huge cabin and IFR capability, but its tricky to land in the "neighbors yard" without breaking anything.
So, it all depents. From the view of a pilot I would choose the new AW 139
!!
Hope that helps a little
RB