What a surprise... I have two different brands of these...
I have the Yoyodyne ER type and a different company...too lazy to go look!
The ER ones are GREAT as tie downs...not so much as sliders. I had a small get off on my bike and because the slider screws on to the base, it doesn't have a great deal of material. Basically it cracked and flew away immediately. Also, you have to wait until the bike has cooled down to remove the slider and install the tie down mount.
The other type I have uses three screws to hold the slider or tie down on to the base which affords you a lot more slider material BUT I had nightmares about the bolt's shear strength and quit using them. To be fair, because the slider and/or tie down mount fits onto a "lip", I'm sure that the stress isn't carried by the bolts.
I just got back from hauling my bike to Knoxville, TN and used my Canyon Dancer. The other major problems with frame slider tie downs are the proximity to the body work and because the mounting point is lower, some ratchet straps start out with too much "dead strap" which leaves you with little pull down room.
Other than that, they work awesome! I obviously suggest that you use a wheel chock with them though to keep the front wheel straight. Something that is not necessary using Canyon Dancers. Btw you can almost always just use Soft Straps to wrap around any frame sliders and tie off that way. I used to do that because I had MoMo carbon fiber grips that I was afraid of cracking.