In the process of doing some research recently regarding a project for southern africa, I was led to look more closely at the performance capabilities and economies of several types of aircraft.
The Q400 appears to be the huge winner with the current price of oil being what it is. I mentioned the 146 as an example of a very capable aircraft whose downfall now may be the fact that it has four donkeys doing what you can do with two props. Given that Flybe have replaced a lot of their 146s with Q400 I'd be interested in comments from pax and pilots as to which aircraft they prefer and also as to the performance/economics of the two aircraft.
As to the Sukhoi program I know little about that....one presumes that it will just be straight fight between them and Embraer for the 90 - 110 seat market. But for the <70 seat regional market I seem to think that now the cost of fuel can means that props are king in this sector.