I cannot comment on the flights from other airports, however I have used the Manchester-Prague service quite a lot recently. I have always found the price competetive against the LCC's.
I would say on average the load factors have been good at least 3/4 full. The interesting fact to me is however that mainy of the passengers are transfer passengers to other eastern european points not point to point traffic.
I would contend that CSA have been quite succesful in attracting this business.