Peak is another Warren Dist. (Nebraska) oil... I have their stuff in my car all the time.
When you see a generic/off brand/house brand oil, flip the bottle over... if it says Wne, or Wpp, it's Nebraska Warren.
All their oils meet spec, and meet all the API and Ilsac requirements. Their personal brands are Mag1 and Accel. Both of those oils are OK if they are to spec for your car.
In my case, I buy auto parts store brand oil made by Warren.. It's practically the same as Peak, Accel, Mag1, AutoZone Brand, Federated Auto Parts Brand, some of WalMart Brand.. and lord knows how many others. It meets API and Ilsac standards regularly, and is a good choice for vehicles that are used for casual service.
ALL of my vehicles currently have a Wne oil in them right now.