I guess what it comes down to really is whats motivating the dessision either way for single or twin? For me anyway I could never see myself having a twin install set up unless its actually was a model like a Me-262 or Learjet etc. with the obvious separate and scale engine pods.....reliability of my single setups has never been a concern whatsoever to date.
Therefor I cannot agree with there being legitimate concern in regard to safety and the reasoning for twin install alone. The wow! factor between twin v single in say an F-15, F-18 is negligible at best IMHO, I remember seeing Tommy Woods beautiful F-18 twin RAM 750 fly at Superman a few years ago and it flew great but that said you would not have known the difference unless you where actually told or snuck a peek under the hatch that it was a twin... I guess some engines have a better track record than others for consistent reliability and of course none of us have likely first hand experience with 'all' the various turbines that are currently on the market! so therefor we form opinions and base our comments and reasoning on the engines we do fly or have flowen