I just traded in my 2015 Outback 2.5i Premium after 30 months. In NC and FL in the warmer seasons I used 5w-20 full synthetic. But being you are in PA (colder climate needs easier starts), I would stick with any name brand full synthetic 0w-20. If your car is brand new, using 0w-20 will eliminate any questions if you were to have an oil related warranty claim. Personally I prefer Pennzoil Platinum, Quaker State Ultimate or Castrol Magnatec. NAPA full synthetic is also popular when it's on sale for $3.59 a quart. Mobil 1 is popular here, but some say it runs on the "thinner" side and may increase the engine valve noise you can hear. Oil brand is really a personal preference.
I loved my Outback, but we needed more cargo capacity. Welcome to the forum.