Unless you plan to use it very often, probably better to rent.
Or check Craigslist and/or Facebook Marketplace. This is one of those things that people buy then never use it and end up selling it dirt cheap because they're sick of it taking up space in the garage.
I've run an Agri-Fab and owned a Brinley. Both did the job. One thing I liked about the Agri-Fab is that you could raise and lower the aerator from the seat. The Brinley's lever is on the side. That's the only meaningful difference I've noticed. I like to raise and lower from the seat, so I'd probably go with an AgriFab if I bought one again.