The 'waterproof' membrane has failed on every pair of boots i've had apart from my winter B2 boots. All it takes is a bit of grit inside the boot, or repeated flexing in one area to damage the membrane in my opinion. The lack of flex in my B2 boots, and their high cuff has probably helped with their longevity. If had to buy a pair of boots again (i won't), i would go for good one piece leather uppers, rather than rely on a membrane.
I hardly wear boots these days, but if i want waterproofing, i rely on my Rocky Goretex socks.