I have a '17 Outback with the FB25 engine. Mobil 1, Pennzoil Platinum, Quaker State, and Valvoline are all good choices. Personally, I just changed my oil at 11,000 miles and put in Amsoil Signature Series 0W-20 oil. Significantly more expensive, but if you join their 'program' by paying, IIRC, $20 a year, you get a very good discount on their products. Been worth it for me, as I am also buying their ATF for my '16 Honda Odyssey. Their SS oil is plugged as a one change a year oil. I like to change every 4-5k miles, just because. So I talked to one of their dealers, who suggested I go with their XL oil.
If you're going to be a shade tree mechanic, take a look at the Fumoto Drain Valve. Ingenious device for changing the oil without having to remove the drain plug.
Also, you might want to consider adding a bottle of Liqui-Moly Ceratec. It's an oil additive that uses Molybdenum and Boron compounds to reduce friction. Gets high ratings. I put it in both my vehicles. Good for 30,000 miles. Good car! Good luck!
