Probably for the money, power, endurance, speed, cabin, rear loading doors, high tail rotor, tough builtness...and proven EMS intererior designs.....the up-engined BK-117 is the right answer.
The BK...once the engine problems got sorted....turned into a good machine for EMS.
The rear loading doors and high tail rotor make hot loading/unloading safe.
Having both side doors and tail doors is a real nice feature when cleaning the interior. The front seat crew member faces forward going outbound.
The two med crew when in the back have room to work and access gear bags.
You have the capability of carrying two serious patients and still be able to work on them.
The 76 and 412 have more room...but cost more to operate....are bigger all round.
My first choice with all things being considered is the BK.
Having seen a tranny cowling go through the blades....and the aircraft bring the crew home safe....really sold me on how strong the aircraft design is.