I have flown the 105, 117, and 412.....hands down the 412.
Much good use of 365's and 76's.
The 105 does a good job, the 117 better yet, and the 412 a very good job.
105...small, hard for the med crew to get to the patient, 117 (with big engines and autopilot) fairly roomy and fast but prone to make the med crew airsick, and the 412 the most capable and roomy. LZ size difference between the 117 and 412 not much different in reality. Plenty of range, lift ability, and easy access to patients with limit being ability of med crew to deal with the patient care needs. Usual crew was two med crew but add one more and two serious patients could be attended to in flight.
Cost issues are a different kettle of fish with the 117/145 being the best compromise nowadays.
The 109 is a poor choice due to cabin space.