The AllPro is nice, but it only covers the back of the diff. Is weld on. I have one, never hit it on anything.
The All Phase looks really nice (I have one waiting to go on in my garage). The only quality issues were associated with a massive group buy that I think got out of control for All Phase. The crux was that the U-joints that hold the plate on got made slightly too small. You can check with All Phase, but I'm sure that this is not the case with their non-group-buy versions.
Several others have versions "in preparation" but since there's no photos, these are by definition vapourware right now ("vapourware" = Pronunciation: (vā'pur-wâr"), —n. Computer Jargon. a product, esp. software, that is promoted or marketed while it is still in development and that may never be produced.)