I think the big problem is that most of us drive to IFSEC. Getting to Excel is a trip around the M25, and I mean right around if you have to come from almost anywhere bar Kent. Then you have to try and get home!
Getting across London from, say Hammersmith to the Excel is painful via Tube and DLR, and it takes over an hour.
London is probably more expensive to stay over and I think from an overseas visitor perspective is going to bust the bank, if not the first year, the next year.
For me, as an exhibitor, its going to cost us much more to be there from an accommodation and logistical overhead perspective.
Personally, I think its a poor choice. I hated trying to get there 10 years ago when we exhibited before and I hated it even more just recently when I visited the area for a day out. I was Nucking Fackered when I got there. Maybe I'm just a grumpy old man. I hope I'm wrong...