I lived about 6/10ths of a mile from the airport until a year ago. Berts is fine. I've bought stuff there before. Their staff is not great, but they're huge and have a huge selection. Its hard for me to believe that the Transit road Berts bikes isn't much, much closer to the airport, its only about 2-3 miles away. Then you can literally just ride straight up Transit to meet the AC route in Lockport. They're always extremely backed up so make sure that you have an appointment if your using them to build your bike.
The thing is, as Jeff indicated, the bike shops along the lake/river cater to touring cyclists to some extent because its a popular place for touring riders to ride. However they are much smaller than the Berts Mega-stores, with their mega-wall stacked to the ceiling with "new" 2007 model year bikes that they're still trying to sell at full price to the uneducated consumer.