This is the classic "make or buy" decision. You can rent by the minute, or own your own.

What the Amazon website doesn't cover is:

- download guarantee. They rent you the antenna, they don't commit to a successful reception (and consequent refund if it fails)

- link status report (needed for a positive confirmation of successful reception.) This is basically a series of SNR measurements

- competition with other users of the same antenna: first-come first served? Maybe your spacecraft needs more storage to save the downlink data if the Amazon antenna is busy.

And of course they don't talk about the competition.