The only horror story I've had with the imports is my 17-50mm Tamron.
I originally decided to get it so that I had something low-light for doing Kathryns gigs with. Ordered it a month before Kathryns gig and the week before it still hadn't shown up. I ended up having to cancel the order etc through the company and getting a more expensive copy from a local shop.
The fun started then though, as the import actually arrived, a week after I asked to cancel. I then had to send it back, and it took 2 months for them to sort out a refund. Well, I say that, I actually had to contact my credit card company and explain the situation and they gave me my money back.
It all came out good in the end though, as the import company at some point a month or two later actually refunded me as well