I agree with Texmex. If your four bikes are worth a few thousand dollars each, you could easily have $10,000+ worth of bikes setting on your rack. A cheap rack is no place for valuable bikes. Hitch mount tray racks are very easy to use and secure bikes very well. Once you buy one, you could have it for 30+ years. Think of it as a long term investment.
Especially for a 4 bike tray rack, look for a tray rack that has a very high ground clearance. It’s easy for a long rack to scrape the ground when going through dips. I have a 4 bike tray rack and I have added a hitch adapter that raises my hitch about 10 inches so that I don’t scrape.
Be aware that the hanging style of rack you are considering may not work with most full-suspension bikes. Frequently the shock is in the way for a hanging style rack.
If you do decide to buy a hanging style rack, you can find other brands that cost much much less than the Subaru hanging rack.