I've seen the damage a poorly built deck can do so i suggest learning the basics first. Even "pro's" can screw up something so simple as how to attach the ledger to the structure, even when it's spelled out for them. This one house was only about 4 years old and they had to rip off the deck and pay about $15-20K in repair costs because the builder didnt flash it, and after that they had no money to replace the deck so do it right the first time. I'd say the deck itself is the fast/easy part, the hand-rails and stairs are where it will kill you in time and cost. But it also makes the deck, in my opinion.
My buddy built a deck at a beach house using interlocking aluminum planks and 10 years later it still looks like the day it was built, according to him. Not cheap but it should last a long time. The deck at my house is about 28 years old, all PT lumber, doesnt appear it was ever stained or sealed, gets pressure washed once a year and it's starting to show it's age. I could replace just the decking but the frame wasnt built strong enough and the other structural deficiencies doesnt make it a candidate for a rebuild. So i'm think patio instead.