Before you fall for the first set that looks good in a showroom, walk the actual space at home with a tape measure and chalk, or just some tape, and mark out the footprint on your patio or deck. A six person set with chairs pulled out needs more room than you think, and if you can't walk around the table without turning sideways, it's too big for where it's going.
Think about how you actually use the space before you think about how many chairs look nice around a table. A small balcony or a narrow concrete patio off a rented apartment wants a bistro set or something with two to four chairs, not a dining suite built for a backyard that could host a wedding. A proper backyard with some grass and a grill can carry a bigger set, and that's where it earns its space, especially through summer evenings when you're out there until it's dark and the bugs show up. If you're in a climate with real winters, think about where the set will live from November to March, because a cushion left out in snow for one season tells you everything about the foam inside it.
The difference between a set that lasts and one that looks tired by its second summer comes down to what's under the finish. Aluminum that's actually welded rather than just screwed together at the joints will hold up to being dragged across a patio by someone who refuses to pick things up properly. Teak should feel heavy for its size, with joints that are pegged or mortised rather than glued and hoping. Wicker, real or resin, should have a frame underneath you can feel through the weave, not just a shell. Check the undersides of chairs and the inside of table legs where the manufacturer doesn't bother finishing things nicely, because that's where corners get cut. Give any chair a shake at the showroom the way you'd shake a ladder before climbing it. If it wobbles standing still, it will be a disaster with your brother in law sitting in it after two beers.
On delivery day, check that cushions actually zip off for washing, that umbrella holes line up with the base you're planning to use, and that any glass top is tempered, not just glass that sounds fancy in the listing. Count the hardware bag before the box goes in the recycling, because missing one bolt means the whole set sits in the garage for a week.
I'd put a modest four seat set on a back deck first, somewhere you can actually see it from the kitchen window.