I looked at the safety locks on all of them and found the DIRECT-LIFT PRO-PARK 8 Standard was the best. (The lock system is just like the Rotary) Works perfect. Had it for over a year and use it almost everyday. If you are in San Jose, CA, then call Tom Tweedie who is over in Santa Cruz @ 831-332-8669. He will talk your leg off but he really knows his stuff. You can buy thru him and he does installs if you need it. He is part of this group.
http://www.bestbuyautoequipment.com/...k8standard.htm
DJ