Although sometimes there seemed to be rather a few filler episodes the show mostly was a battle for control of Atlantis.
The battle was finally won and the whole thing was flown back to Earth. During this time there were a number of enemies each rather powerful in their own way. But each lacked the ability to adapted like the team on Atlantis.
There was constant upgrades, battles and things to find. Much like SG1 the Stargate was of heavy use. However there was far more enthusiast on ship to ship combat which was at a point in Stargate universe when the game was getting to powerful and easier to win.
In the end, there was only one out-come.