Tour through this website to get more info on the Stryker (or at least the "parent" vehicle behind it).
http://www.army.forces.gc.ca/lf/Engl...=48&uSection=1
As you'll see it is essentially a platform on which various "packages" can be mounted. (Use the "More Info" link). It is absolutely NOT intended to replace tanks but IS definitely more robust than HumVees. The beauty of this one is in it's size/weight and ability to be delivered by air in quantity.
Oh...the virtual tour is worthwhile too.