I fly a BK117 in California in an EMS role. It is excellent and very popular in the states. The B2 model is very strong and performs well in high DA situations. It's great for night operations since the cabin is separate from the cockpit, no bother from the patient or the interior lights. It's a stable platform for IFR but I understand that it doesn't have the range to be very effective. The medical crews like it as well. Two patients or one. The interior is key, take your time in designing it.
Let me know if you need any more info.