Rear Bike Rack: What To Get ?

Hi Folks,

Thanks for all the previous help.

Want to help son get a rear mounted bike rack for a 2015 Subaru Outback.
Amazed at how many mfg's and variations are available.

Would appreciate any recommendations for a:

2 bike rack
And for a 3 bike rack.

What makes them "better" ?

As I know nothing about this kinda item, would appreciate any
hints on what to look for, absolutely get in way of features,
and most important, probably, what to avoid.

Something really safe, as sure don't want the Rack coming off, either
with OR without the bikes, on the highway !

Also, the Rack should be easy and straight forward to put on or off
the car.

**Or, do most of you folks just leave it on all of the time ?

Any that do a better job on not obscuring view out of back window ?

Thanks, as always,
Really appreciate the help,
Bob