Kevlar is sorta a stupid choice for a stock laminate, I wish they made more out of carbon. As a composites guy, I can't see any reason to make a stock out of Kevlar, other than the fact that people in the shooting area are well aware of Kevlar in vests. Of course there are good kevlar stock.
An advantage to buying laminate (both are actually laminated, one is wood laminate, the other is a composite laminate) sight unseen is that it is normally stiff enough. Just saying Kevlar is in something means almost nothing as far as quality or performance is concerned. I hate mushy stocks that deforme under sling pressure etc... Also, it is easier to make changes to a woodlam stock than a composite fabric one of the type where all the strength is in the skin. If a laminate stock is light, it may not be impregnated and it won't be waterproof under the finish.