I'm using a Thule roof rack with fork mounts. I've never had a problem with stability or safety. Before that, I had a Saris roof rack for several years, likewise with no problems.
I prefer the roof racks that clamp the fork dropouts because I believe they hold the bike more securely than racks that hold the bike upright with the front wheel on. Also, I think that configuration presents a slightly lower profile to the wind. I use a "bra" on my bike to protect it from rain; it also looks pretty slick!