Newer construction generally keeps near-term repair costs down, which matters for an investor modelling year-one cash flow against a mortgage that compounds semi-annually. The tradeoff is a smaller renter pool than a neighbourhood near the university or a major employer, so vacancy days can be the bigger line item rather than maintenance bills.
A legal, permitted secondary suite is the detail that actually moves the numbers, since only permitted income can be underwritten by a lender. An unpermitted suite might rent the same, but it will not count toward financing.
Getting the rent roll and the suite's legal status confirmed before an offer is the difference between a good number and a guess. Get your hand-reviewed valuation from Joel Dyck.