The marketplace gives consumers access to more than 300 products created using a 3-D printer.
The two retailers led Internet Explorer and Firefox tests, respectively.
L.L. Bean finished in first place among large retailers in October web site availability tests, says Compuware Gomez. Last month, LLBean.com posted an Internet Explorer availability score of 99.99%. Amazon.com led the way in Firefox testing with a 99.99% rating.
Staples.com was second in Internet Explorer tests with a score of 99.98% availability, followed by JCPenney.com (99.96%), OfficeMax.com (99.94%) and Newegg.com (99.93%).
In Firefox testing, Newegg.com, Williams-Sonoma.com and HPShopping.com, tied for second place with 99.96% availability. QVC.com and HSN.com were next, tied at 99.95%.
The average Internet Explorer availability for the 18 retailers measured in October was 99.29%, according to the Compuware Gomez Benchmark study. The average Firefox availability for the same group of retailers last month was 99.54%.
Availability is determined by the percentage of tests that load correctly.