Interesting comments, one more reason forums like this are so useful. I've been using two Deltas, one for about two years and the other is a new blaze orange I keep in the truck.
I keep them in their storage tin most of the time, but I use them maybe once a week pretty regularly and they seem to work well- with a much more robust flame than a disposable, more like a torch, and when adjusted properly they will stay lit in a pretty strong wind.
I've noticed you have to fiddle with the adjustment a little until you get the flame right, and they don't work as well when they're low on fuel. The issue of the continued flaming after release is supposedly adjustable, mine did that when new and after some tweaking work consistently well.
I would agree on the backup fire, no lighter is worth betting the farm on. My backups include a Gerber StrikeForce and good old strike anywhere waterproof matches in a sealed plastic tube, but I have yet to be disappointed by the Delta as long as I keep "bastard gas" LOL in it.
Of course, having read these comments, I will now be super critical of the lighters and they'll probably break.