I wouldn't worry about flying the Q400 there is very little to seperate them from a jet from a passengers perspective
noisier, slower, narrower seats, less cabin baggage space (watch out for the £40 charge at the gate), no hot food, flies lower so more in the bumpy weather.
Agreed, SOU is woefully under based with E jets compared to other large Flybe bases like BHX and MAN but there is little competition (look out for the Veuling A319 and Air France/Regional E175`s this summer) and the BAA have yet to invest in SOU and provide enough parking stands for them!!