I got the more expensive choice from Napa. Those things are beefy. You wont have to worry about replacing them again. They have a grease fitting also, which is a plus.
You may want to consider sticking with an arm that has non-greasable ball joints. Those are teflon lined low friction joints as designed as are the lower ball joints (if you install the correct arms). The feel of the car can be impacted if you use a conventional metal on metel ball joint.