I reackon its down to either the -42 or new s340's. Both have their own advantages/disadvantages.
saab- already proven, no real re-training for crew or engineers and a sim close by for checks, ( i beleive closest -42 sim is in thailand)
atr- first of type but so similar to the -72 anyway. more pax but still only needing 3 crew, plus alot of spares, engineers and knowledge with mount cook. I hear after about 7 years the atrs start becoming hangar queens though.
too close to call. Below mda is probably right, depends who offers the most beer.