I have a Thule hitch mount bike rack. Easily holds 4 bikes. My car only has a class 1/2 hitch, so I usually don't carry more than 120 or so pounds of bikes (tongue weight is rated at 200lbs, and I only go 60%), which means at most 3 big bikes, or 4 XC/AM bikes.
Benefits are it's super easy to use, no worries about excess weight on the roof, no worries about hitting a low ceiling. The rack mounts on in 30 seconds, and I put it in the trunk if I don't want it hanging off the car. Bikes mount in seconds.
Drawbacks are low hitch height (which means it can be hit backing down a sloped driveway), and rack sway. My car hitch is pretty low, and I doubt you'd have the same problem on an Element. For rack sway, I got a basic stabilizer, and it works.
Factory roof racks are only rated at about 80lbs.
If you have a 2" hitch, then the weight of the bikes won't be an issue.
It is easy to dodge our responsibilities, but we cannot dodge the consequences of dodging our responsibilities.
- Josiah Stamp
Every time I see an adult on a bicycle, I no longer despair for the future of the human race.
- H.G. Wells