Well, I'm not sure which benefits were expected, but everything is highly expensive in London (even by western-european standards) and distances are huge. In Birmihgham the exhibition center was just next to the airport, the city was compact and nowadays there are various low-cost flight options to this place from the rest of Europe.
The timing is not so bad, in most European countries the summer vacation comes in August, so in June most people are still at work and most manufacturers try to make key announcements at IFSEC as it was traditionally the most prestigious exhibition event for this part of the world. But now things are changing. Last year I also visited Security Essen in Germany - it is hosted in end of September (a more suitable time), it is much easier to access (visitors from some EU countries can go by car), the expo center is huge and there is growing attendance. The only disadvantage is that it is hosted once per 2 years. But otherwise it is becomming the most important security industry event for Europe. For the next show there I can make a short report for you guys, so that you can have an idea.
The Intersec is definetely also getting very intresting, I was there in this year's edition in January and it had a really global approach, along with all others advantages - the perfect infrastructure, numerous hotels, cheap taxi transport..not to mention the endless entertainment opportunities in Dubai :)