My favorite online banks are AmsterdamMarijuanaSeeds and CropKingSeeds out of Canada. I'm in the US and have had no shipping issues. I had one germination issue with seeds from AMS, and they gladly replaced.
AMS:
Blueberry420 Auto
Light of Jah Auto
Lemon Haze Auto (Had issues, replaced w/good seeds)
Crop King:
White Widow Auto
Black Indica Fem
The only seller I've had a problem with is GreybeardSeeds. They are not a seed bank, but rather buy large quantities from other retailers. They have no connection with the breeders. They also have a disclaimer that the seeds aren't guaranteed to germ. When I complained about seeds not germing but that I understood the disclaimer, the owner replied that they "would have" given me free seeds if I had asked, but since I didn't want them, "good luck." I complained about this terrible customer service, and got a rash of insults and reasons why it was my fault the seeds didn't germ.
Most seed banks will offer friendly service and replacement seeds, and most breed their own or are authorized to resell from the breeders. I also found out that Greybeard was not authorized to resell the seeds by the breeder, FastBuds.