For a true long range rifle I would get the Vortex Razor AMG 6-24x50. For predominantly long range shooting it has an excellent FFP reticle, turrets and good glass.
For a rifle that would also be carried for general hunting some and closer shots expected, I would lean towards the Leupold VX-6HD 4-24x56. It has a better zoom range and the SFP reticle would be easier to see on fast close shots and still work great long range.
Also depends on if you want to not have to use dope cards or an app for long range shots. the Leupy has the CDS turrets that you can have matched to your load. That brings its own can of worms along with it though because changes in elevation and weather can affect the accuracy of it and you have to have a different turret for different loads.
For a long range rig, I think it would be the Razor hands down.
I think christmas tree style reticles would be much more useful with an FFP reticle. Although the ability to quickly use correction based on last shot would work well in FFP and SFP.