Dave,
I used one just to see how it worked, and even though the angle looked a little more severe, I was getting no ill effects after a few days.............I didn't leave it on because I was having no problems with the stock slide.
IMO it's one of those boarderline things. I wouldn't want it a millimeter beyond the position the SIMS puts the string and cable and I would watch it very closely for excessive wear. Inspect the area after every shooting session.

If you want to try the Saunders slide you'll have to use your own judgement as to what is TOO much, and pay attention to the wear.

Many guys are going to the Hicks slide just because it falls in between the SIMS and the factory version.......just enough clearance, but not pushing the line where you are worried about it.

I would use the SIMS if I HAD TO.......it worked. But I feel much better about the HICKS, or in my case the factory one.