From the description sa websites, water & dust resistant naman yata. Hindi waterproof if you're thinking of submerging it in water

I have rain gutter sa sasakyan ko, so not really a problem using the roof boxes since may provision naman to use the rain gutter. Not sure lang how strong the rain gutter is - kung ilang kilos kaya, while the vehicle is moving on good, as well as bad roads.

The reasons i would rather prefer Thule boxes from the roof rack baskets are:
- mas aerodynamic sya
- not needing any more separate cover and tie downs
- mas water resistant than those covered only with tarpaulins
- comes with locks, such that you have peace of mind na walang magnanakaw nung mga gamit mong nasa roof while leaving your vehicle. unlike roof baskets na kayang-kayang tanggalin ng mga magnanakaw yong mga tali, then off they go with your belongings.
- mas madaling tanggalin once di mo muna sya kailangan.
- cool factor...hehehe.

Cons nga lang:
- most likely mas limited ang capacity than roof baskets
- maybe, mas pricier