Premium Economy is the class that is likely to get the most blank stares when you're telling people which ticket you've booked. It's neither business nor is it basic economy - it sits right between these two. This cabin is offered on all major airlines that fly internationally, although some may have a slightly different name for it.
Depending on the airline, passengers can expect extra leg room, extra recline, extra seat width, priority boarding, priority luggage allowances, extra earned miles, amenity kits, larger in-flight entertainment screens, upgraded headphones, and plated premium meals.
This class is most likely not worth it if you're on a budget. Take the extra money and spend it on an upgraded hotel or experience at your destination. However, if you're looking for a special perk before you arrive, or simply need to not slog into your destination it's definitely a step up from regular economy and it might be worth a look at business class if you're on an extra special trip.