I use both. Neither are probably really better than the other. But I prefer vertically split because they are less obtrusive. And I've never lapped vertically split rings and never felt I had to. I've never had a scope slip in vertically split rings but I have in horizontally split rings. For instance, a failure to lap Ruger rings supplied with a Ruger gun is an accident waiting to happen. Great guns, horrible rings.

As far as being a rain collector: non-issue. Water can get get under both.

As far as the scope coming loose when you detach: that's an issue with Talley fixed permanent attach rings because they are literally two halves held together by two screws. (But they are marketed as "fixed" rings, so detaching them will require reinstallation.) But its a non-issue with Warnes, and a non-issue with Talley QD and QD screw lock because they are two-halves that attach around the scope first, and which has a third piece that clamps to the base. I've found Warne QDs and Talley QDs to return to zero very well.

[Linked Image from i.imgur.com]
https://vcdl.org/