BFG Traction T/A's have a 100,000 km limited treadlife warranty. The Falken Ziex 512's in a 65-series have a 96,000 km warranty. Thing is, don't be fooled by the treadwear ratings. Although a higher number means greater wear, it depends on a lot of factors (driving conditions, rubber compound, speed rating, etc.).
The only reason why I would go for a BFG is the number of dealers that can help you out during a warranty claim. You said yourself that it's hard trying to find people that carry Falken's in stock.
If you're still insisting on Falkens, then give Steelcase Tires a call up in Markham. I know they were suggesting the 512's for me initially, but I eventually took to Toyo.