Upgraded suites tend to have many features that are appealing. This is because the buildings are usually quite old and the only way to get prospects interested in the community again is to upgrade. From playground and pool amenities to new sink fixtures, the landlord is going to do what it takes to ensure that his or her property is appealing.
So when visiting a rental, check for the upgrades, notice the cleanliness of the apartment--pay particular attention to any possible rodent or insect droppings along crevices and under cabinets, and most of all use your smelling and touch senses. Sniff around for bad smells, notice soft spots in flooring walls, and wood surfaces. By doing these things, you are checking for mold, mildew, and shoddy maintenance work.
See example photos below: