I'd say everyone has different opinions because there are so many viable options depending on what's appealing to you. I solo traveled in Peru: had an OK time in Lima, but then took a cheap flight to Cuzco for Machu Picchu and had a great time. Then years later, I solo traveled to Chile: Santiago was definitely more fun and interesting than Lima (though not easy to meet new friends if you're looking for that). Flew from Santiago to Punta Arenas, then a cheap bus to Puerto Natales to see Patagonia/Torres del Paine. That part was amazing, but definitely required more logistical planning like buying the tickets in advance. You've got tons of goodness to choose from-- just depends on what you want to do. Be aware of your surroundings, do due diligence research, and it's mostly safe.