I just purchased a 20" on Amazon. I contacted Finnex before I made the purchase and was told it would be about two weeks before it was back in stock with them. The price was just a little bit lower on Amazon.
Packaging wasn't of the highest quality but the fixture came through the shipping process without damage.
The fixture is outstanding and looks great on my 14 gallon low tech tank. I only wish the mount would work on a tank that has a glass top on it.