First of all, I'm used to my lux which has the rubber in the bag collar, and the rubber gasket on the inlet spout which virtually eliminates any leakage or blow by. Lately I can't resist checking other makes. What I've noticed is that many brands, the pre-motor filter is covered in debris to some extent, some more than others. (by debris, I'm not talking about powder type dust, I'm referring to grit, sandy like substance) Either the bag has burst or the gap around the inlet is large enough that the dirt can get sucked out of the bag from around the inlet. One would think that this could cause a hepa filter to clog prematurely. Which brands/makes seem to be more problematic than others? How do the so called higher end vacs such as miele, riccar, sebo (just to name a few) fair as these models don't appear to have a seal around the inlet either??