Those locks don't provide much security. The cables can be cut in seconds with bolt cutters (standard bike thief tool) or cable cutters, and the lock cores can easily be broken with a big screwdriver.
My rack doesn't have locks, so I use a 6ft Onguard armored cable lock:
Armored Cables ? OnGuard Bicycle and Motorcycle Locks
Even that can probably be cut by bending it to separate the armor links, but most thieves haven't seen one before and don't know that. Maybe I shouldn't even mention it here. U locks are the best, and I think the bigger chain locks are hard to cut with regular tools.
I have a 1upusa rack. I like it, but it's really heavy for aluminum. It's expensive, but I got it for my last car because it was a tray style rack that could hold 3 bikes on a car with a 1 1/4" hitch and fold up to fit in the trunk when not in use. If I had to replace it, I would probably get a Kuat rack, which is surprisingly light even though I think it's mostly steel.