Saabs are the smallest cross-section comparing to all competitors. Many people cannot stand up in cabin without tilting their head. Extremely nice when it is a de-boarding time. Also because of smallest cross-section overhead bins are pretty nonexistent. You can fit a very slim case like laptop bag, nothing more. In the winter capacity of overhead bins are not sufficient to accommodate overcoats etc. Toilet is a joke. Galley is tiny.
The SAAB is not camparable to the ATR or Q400 for cross-section as it is only 3 abreast seating. The SAAB seats generally are wider and have more seat pitch than the ATR and DASH 8 due to this. Agreed the overhead bin space is limiting but this is not a huge issue if the company has good policies for excessive items in the cabin. Any toilet on a turboprop is for emergency use only, especially if you know how well cleaned they are.
The S2000 engine is a version of the C-130J Herc engine the AE2100 so it cant be that unreliable. Any reliability issues in such a small fleet would be compounded due to the lack of operational spare aircraft to call on. The dispatch reliability articals quoted are from 1996 a year or two after the aircraft entered service, most if not all aircraft have issues early on and many far worse than 98%.
Noise level in the 340 is bareable and better if it has the ANC system. The S2000 has ANC similar to the Q400 so has good noise and vibration supression compared to other turboprops.
Most of this comparison to the older aircraft is a waste of time as SAAB will no doubt introduce an updated package that includes all modern avionics, engine, noise suppression and seating.
There are people who switched from SF340 to ATR42 or Fokker 50 even they had no prospects of more passengers. Simply the difference in total operating cost is pretty marginal and you getting much more seats as a bonus. I have first hand experience (or should I say misfortune?) operating these birds and therefore my opinion is a bit more based on a facts as opposed to observations from outside.
Sounds like rubbish the ATR and Fokker burn at least 10% more fuel than the 340. Engines and systems are probably of very similar costs however i would say the 340 is still less. They also have to carry an extra flight attendant under present rules. Many of the operators that have made this switch had to drop out of smaller routes and some went broke.