When weighing out the advantages and disadvantages of twin-engine versus single-engine turboprop aircraft, most operators will think of safety first.
Having the redundancy of a second engine means that in the case of an emergency where one engine quits and the aircraft has enough altitude, the second engine will provide the pilot with the ability to navigate to an emergency landing location.
Aircraft with twin engines also generally have more backup components such as twin starter generators which provide additional safety in the event of failure.
Beechcraft King Air B200 - 1983
Beechcraft King Air E90 - 1975
Beechcraft King Air 200C - 1981
Beechcraft 1900 - 1992
Beechcraft King Air C-90 - 1981
Piper Cheyenne II PA-31T-620 - 1982
Beechcraft King Air C90A/B - 1969
Beechcraft King Air C-90 - 1974