The QUAY 500 was a clone of the North Star Horizon offering some technical improvements compared to its competitor: a standalone single-board instead of a backplane and several S-100 boards, Direct Memory Access for better disk access performance, on-board expansion capabilities for additional parallel and serial port and higher disk capacity.
The 500 model was sold with two 200 KB double density 5"1/4 floppy drives, the 520 model with two quad density 400 KB drives.
In spite of these technical advantages and a price 20% lower than North Star's similar models, the Quay 500 series do not seem to have been marketed for long.
Phillip Good comments:
The Quay computer was not sold to consumers but to OEM's who would package it around some kind of accounting package and sell it to professionals--accountants, dentists, physicians, and so forth for use in their offices. Its wooden case was intended and succeeded in making it look professional in contrast to the rinky tink plastic and metal contraptions which are standard today.