Shrikes have same profile as Warriors save one is Jump Infantry with armor 5+ and the other is Infantry armor 4+ w/ access to all the same biomorphs and upgrades
Considering that you are likely using them to move your synapse forward and relying on Cover as much as possible until you get into melee, and the fact that they are far more likely to die from being hit by Krak Missiles and Meltas which ignore armor 4+ as well, why wouldn't you select the option that is more mobile and capable of jumping behind or over LoS blocking terrain?