I'm using the Sure Drain on two of my cars & would be using it on all of them if I could find them again. Yes, the valve is slow to drain oil, but the "coupling" is so easy to attach...beats breaking out a wrench and cranking on an oil plug at an odd-angle.
As for breaking off the valve due to clearance, it would be pretty difficult in my applications. Unless someone has a unique oil pan that drains from the bottom, and not the rear, I don't really see how the SureDrain would be any more of a clearance issue than the regular old drain plug. It's not like the exposed part of the valve is that much longer than the head of a drain bolt...