The article I refered to also has a quote that the Saab 2000s are so expensive to maintian that they do not provide any cost advantage over the Saab 340s despite being 1/3 larger. Plus they are in a weight category that makes them rather expensive for a 50 seater when it comes to charges, fees etc. Add to that that their superior speed isn't really needed on Loganair's network. So bring on those ATRs - it will also give Loganair the option to add a few ATR72 depending on future expansion plans.
Islanders are to stay according to the article, Loganair looked at alternatives like the Quest Kodiak or the Caravan, but they lack the performance required around the Orkneys.