Twins v. Singles  

It is true that even the early turbines like were pretty dang reliable.  Yes, the C-18 had its problems, which were cured with the C-20. And the early LTS-101 was a grenade looking for a place to explode - but! - it did okay in some airframes (like the 117), just not the Bell 222.  But old habits die hard - the guys flying those new turbines were the ones who came up in pistons. And it took them a long time to gain a trust in the turbines and get over the paranoia that the engine was about to fail at any moment. Thus, it's why Agusta came out with the 109 (which was basically a twin-engine 206L with retractable wheels), Eurocopter brought us the AS-355 Twinstar, and MBB gave us the BO105 and 117.  Bell futzed around gave us twin-engine versions of the 206, but never really made a serious effort to market or produce a light-twin.

For a while back in theh 1980s, it looked like every EMS ship would switch over to be a twin-turbine. And it was something of a shock to the system when 206L's and 350's began showing up in that role. And now look at that segment! So many 407's and 350's, and nobody really seems to care anymore that they're singles. How times have changed!