good thread, lets use it…
Imo with all the above said I would say go like this :
good selection of helicopters from difrent devs ( Huey in the works, in the meantime Bell412 from X-Trident will do great job )
+
whole world scenery
'=
X-Plane
Most of P3D helos are lacking in the basic flight dynamics regimes.
Btw regarding DCS Huey. First I was litle bit confused not to say disapointed.
Then I visited helisimer page to see what these guys said about it and I was like ’ exactly my thoughts ’ 
When I first downloaded and installed DCS UH-1H last year, I was very disappointed in it. I had heard just how good it was, and had just purchased a set of Pro-flight trainer Black Lynx flight controls for my PC. To me, the flight dynamics didn’t represent the forgiving pilot friendly flight characteristics I had always heard the Huey family was famous for. Instead, it flew like a Robinson R22 on a half a tank of gas with a 2 to 3 second delay control response in gusty winds.
www.helisimmer.com/reviews/review-belsimtec-uh-1h-for-dcs/
He then continues that PC upgrade made a diference in his initial feelings but with my 60fps in Insta Action mision I dont know if hw upgrade will cut it for me also.
Not necessarily unrealistic, and its fun, but not what I was expecting.