Lots of advantages to either weapon so begin your research and choose the one for you. In fact why not get both, a lot of us here do, myself included. If I could only have one, the AR is more flexible.
You should do a search here, too. There are countless AK vs. AR threads.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek