They recently opened several locations in Scottsdale (and possibly other areas). My impressions are:
1. Significantly more expensive than In-N-Out.
2. I prefer Five Guys fries
3. In-N-Out does an exceptional job in keeping their restaurants clean and their employees are very polite. So far I don't see the same with In-N-Out.

Even getting the "little" burger at Five Guys I end up spending around $8. Getting the double burger at In-N-Out runs around $6. This includes drink and fries. Obviously you get more fries at Five guys but it is more of an order for two people to share.

Personally I don't think In-N-Out has anything to worry about.