The fiber strand filler is stronger and has much much more fill then a regular filler.
Fiber reinforced filler also "claims" to be waterproof but they are NOT. All the fiber reinforced fillers have the same amount of talc if not more talc then regular filler.
Granted they are water resisant but NOT water proof big difference.
A good quailty filler like Evercoats Rage Gold will out perform "Bondo" It spreads easier, sands better and also feathers out nicer.
A cheap filler will in the long run cost more money because of the added sandpaper usage needed to level that cheap filler. And dont forget the added time and effort...Eric
