Somewhere on here I posted the "Rules of Combat". One very important one that applies here: Always remember that your gear is made by the lowest bidder.
That applies to ready made survival kits. With the exception of Doug's kit's of course. (Yes, Doug I'm groveling, sucking up and CYAing!) The critiqes of many ready made kits on the main ETS site make that point quite unambigiuosly. The better one's are a good place to start. But they do need to be checked, supplimented and argumented with other gear.