Two strategies, and most people pick one without really deciding to.
Cash flow means you're chasing rental income over appreciation. Properties where the rent covers the costs and then some, month after month, regardless of what the broader market is doing that quarter. Steady. Less exciting. Lower ceiling, but also a much lower chance of a bad surprise.
Capital gains means you're buying somewhere growing and waiting. Less involvement day to day, more patience required, and a payoff that only shows up when you actually sell, which could be years out, which is its own kind of risk that doesn't show up on a spreadsheet the same way.
The tradeoffs aren't complicated once you see them side by side. Cash flow properties tend to sit in secondary markets, appreciate slower, and need more hands-on management because more tenants means more turnover means more of everything. Capital gains properties tend to sit quiet for years, generate nothing, and then either pay off enormously or don't, depending on timing you mostly can't control.
Neither one is right.
It depends what you're actually optimizing for, and most people haven't asked themselves that question directly. Passive income now, or wealth later. Low risk, or higher ceiling. Immediate, or patient.
I've landed somewhere in between, which feels like a cop-out answer except it's also just true. Cash flow properties in the regional spots, holding the costs down. Growth properties in the city, letting the rental income from the other side cover the wait.
You don't have to choose one philosophy and marry it forever.
Most of the investors I respect run both at once and never talk about it like it's a strategy. It's just how the portfolio ended up looking after enough years of doing what made sense at the time.