I agree for driving, Birmingham much more suited. All London accommodation seems way over normal rates, and if there are a few of you for 4/5 nights I can see how that won't be a welcome addition. A hour on the tube wouldn't bother me, I love the tube and the dlr.
I associate IFSEC and Birmingham together, not sure if it will feel like IFSEC in the big city. Agreed it will be the year aft it moves there when we see how many people visit that will indicate if it was such a good idea. Wonder what will be at the NEC in its place.