This is a very subjective question. Alpharetta has many solid builders and a few that have had past issues - but most of those don't last for obvious reasons.
Your best bet is to align yourself with an experienced Alpharetta agent that has plenty of new home experience, each builder and community is different and there are variables. Get an agent, dealing directly with the site agent means that you lack client level representation. There is no charge for representation, it's silly not to take advantage of that.
I have five new homes under way in Alpharetta/Johns Creek right now, I'm familiar with builders as well as value trends in the area as I'm also an appraiser. I'd be happy to help you, just drop me an email or call - thanks