I can't comment on later models of the ATR42 series, but when the decision was made in Talair to buy two DHC8-100 aircraft in the early 1980s, the ATR42 was rejected due to lack of an APU and it's short field performance was unsuitable for Talair's needs in inter Provincial services.
At the time three ATR42s were operated by Air Queensland and their operational staff agreed with our assessment of the two aircraft types.
The ATR may be OK for specific contractual services or main center services, but at the time the ATR42 could not compare to the DHC8-100 at places like Chimbu, Mendi, Tari etc.