Birkenstock (est. 1774) is a parent company to Betula (est.1994) and aesthetically, the sandals are very similar, with overall quality and price as their major differences. The Betula branch is a more accessible Birkenstock branded sandal, reaching the masses, especially at the price that Costco is selling them for.
Check your local Costco for the Gizeh toe-sandal in genuine nubuck leather. They are a bargain at $39.99 and come in two colours: brown nubuck and bone/beige nubuck.
One of the Lofty Goods' writers picked up a pair today and her feet (and wallet) are going to be happy this spring and summer!