I purchased my rack from etrailer, and am more than satisfied with their service and prices. Up to a point, It seems like you get what you pay for when buying a bike rack.
I bought a Thule Double Track 990 XT, and it has been a great rack. I have hauled bikes on it for over 6000 miles without any damage to the bikes. It replaced a "hanging" type rack, which I was not happy with.
One of the problems with a platform rack is interference with stop light and turn signal visibility. A lady almost ran into me when she did not see my turn signal. I have not been stopped by the police for obstructing the view of my licence plate during the 3 years I've been using the rack.
Our touring bikes have racks and fenders on them so I chose a rack that secured the bike using the top tube. If your bikes do not have fenders, you can use racks that secure the bike to the rack using the bike's wheel.
This is my solution the the visibility issue:
The light bar swivels, allowing the lights to be seen when the rack is in the stowed position or in the loading position. Building It was a fun project, and it turned out well.
Yakima also makes a similar rack.
https://www.etrailer.com/Hitch-Bike-...ma/Y02468.html