I don't know of anybody that uses the 5/16" but was thinking about it before I bought the 1/4" that ovaled. The smaller diameters have had no ovaling problems that I've heard of.

The good thing is that G5 will replace the peep if it ovals on you. The bad thing is if it does you have to remove the darn thing and serve in another one.

I have not heard strang cutting issues.