The biggest pro in favor of taking the Oregon Trail was that it was an established route with many other pioneers taking it. If your wagon broke an axle, there was someone else with a spare you could barter for. If you ran short on food, there was an outpost along the way with extra supplies. In addition, your guide did not need to be exceptionally skilled as all you had to do was follow the dirt track, thus lessening the chance of getting lost.
The United States actively encouraged the settlement of the West. This was done both with the Homestead Act and by establishing Army forts along the path to protect the pioneers. The forts provided not just safe havens to rest and repair but also housed cavalry detachments. These mounted units would patrol the trail and establish a semblance of law and order. Because the Western states were still territories, the U.S. Army did not violate the Posse Comitatus Act by patrolling this region.
The Oregon Trail passed through a number of Indian territories. The Indian nations were composed of both native Western Indian tribes and Indian tribes that had fled from the East. The raids added up to almost 5,000 deaths until the Army started putting them on reservations. There was a spike in raids once miners started foraging into the Indian reserves for gold during the Gold Rush, but this too was put down.
The biggest con to taking the Oregon Trail was the prevalence of disease on the trail. While strength in numbers may have helped with fighting off Indians, it also lead to the spread of dysentery and other communicable diseases. Pneumonia was another concern because of the lack of rest pioneers had and the constant cold nights.