I have the set but don't use them very often. I like them when I need to work a nut in or out of place, because it's easy to release by grip and allow the pliers to expand around the nut as I reposition and clamp down again. Like a poor mans ratcheting wrench. But it takes a few extra seconds to get the jaw spacing adjusted properly. Usually I'll make 3 adjustments before I get it exactly where I want it. With a regular adjustable, you can reach it into a space, flick your thumb a few times and it's snugged down. But of course, repositioning an adjustable wrench is a pain, if you need to turn a bolt 10 turns.
So, in most cases I'll reach for a channellock wide mouth adjustable to crack the nut loose, then spin it loose by hand or grab a ratcheting wrench if it's too tight to spin loose by hand. The knipex is a nice design and well made, but that initial adjustment is a little fussy.