Having use both now I thought I would set down and figure out the differences between the two ghost ring setups, and share & compare with you guys.
First we will look at the XS sights system, cause they are the first ones I used. They are very easy to adjust and are reliable in thier setting. I can't see how it could ever come loose and chance setting because post has to rotate to change elevation, and you would notice it. The XS has the best front post. Its flat top post with center white line makes precision shooting much easier than the factory bead or WWG fiber optic bead. The only real durability concerns would be for the set without the protective dog ears, the appature could possibly snap off. The long skinny front post could also possibly break. Chances are that neather would happen, but its possible. The XS sights also sat quite a bit higher on the rifle than the WWG which was a little more in the way when using the scout scope, It wasn't really a problem, you can look right thru it but it was a little annoying.
WWG sight is a lot lower on the rifle and that seems to be a little faster for me to aquire. The large fiber optic bead is increadibly fast to aquire but can obscure a lot of the target. The WWG is just as easy to adjust but does require an allen wrench. The fiber optic bead really glows in low light and the cutaway hood does offer a little protection to the front bead. I think it will work great in conjunction with a weapon light for use in the dark. The WWG appature is also threaded to accept williams screw in appatures so you can place a smaller appature in for more precise aiming. A few drawbacks are the glowing bead while quick to aquire is very hard to aim precisely and covers up quite a bit at longer ranges, and the allen head set screw. I try to sight it in for a six 0clock hold, but even still the size of the bead makes this a 125 +/-yard sight. The allen head set screw is what holds the appature in place, if it were to work loose and you didn't have the allen wrench you would be unable to use the sight and it could possibly fall off and get lost, a little lock tite will go a long way to fix that.
In conclusion they are both very nice sights. If I was going to only have ghost rings on a rifle it would definately be the XS sights. They are just much better for longer range shooting, and without the scout scope you wouldn't have to worry about how high they set. When used with a scout scope the WWG sights are great close/fast sights and would work well out to 100 +/- yards and your normally going to use the scout scope for rangers longer than that anyway.
here is the WWG sight
XS sights
