Read "Escape from Brussels", in EU Referendum, June 24, 2011.
Here are some comments of mine on the topic raised:
Aside costs, IMO in the web era, EU affairs coverage needs more analysis less reporting per se hence not on location.
The core of politics coverage, in national politics around the world, and in EU/Brussels/Strasbourg is/should be the coverage of the new policy and legislative proposals. This requites a lot of reading which need not be done on location, especially since most documents etc are now available online.
That is why IMO, monitoring and analysis of EU proposals, be it my press or "interests", needs much less physical presence in Brussels/Strasbourg than a few years ago, eg in 1991-1994 when I was posted in Brussels.