I have the Leica PRS 5-30x56 L-Ballistic, the Zeiss S3 425 and the Zeiss S3 636.
I've been very happy with my Lecia PRS 5-30x56 L-Ballistic. No issues over the course of 2 years.
I believe that the glass on all Leica PRS and the Zeiss S3 is very good with no CA and clear edge to edge.
I had planned to buy another Leica. But when Zeiss introduced the S3 at such a great price with a few good reviews, I decided to take advantage of a pre-order sale and purchased the S3 425. I'm glad that I did as the scope is very good and much less expensive than the Leica. It's also more readily found to be in stock with one of the Hide suppliers.
After having the S3 425 for a while, I decided to purchase the S3 636 for a new build. Again that was a much lower price than the Leica and on sale thru a Hide supplier. Unfortunately, I'll have to wait for my CDG to show up before I can spend any time behind the S3 636.
You cannot go wrong with either the Leica PRS, unless you don't like the reticle, or the Zeiss S3. I will say that I prefer the zero stop mechanics on the Leica as well as the spline interface between the turret wheel and the reticle adjuster. This spline prevents any slippage of the turret wheel. On the S3 turrets, if you don't tighten the three set screws enough, the turret can slip while dialing.
So I went with another S3 mainly because I felt it was equivalent, less expensive and readily available.