I bought the Denise set and am quite happy with them. I wanted a set that I could take when I fly without having to worry about arguing with security. The Denise are plastic (or resin they say) so are not an issue. Also I used some Clover bamboo circular needles (not interchangeable) and hated them - the yarn caught on the join and drove me nuts - this is not a problem with the Denise - they aren't as smooth as the Addi Turbos but some people think those are too slippery. And, like others, I struggle with finding the right size needle - I usually try 3 or 4 before I settle in for a project - that would cost more than the Denise set right there.
I did break the join on one cord, it just snapped off. But I sent it in to be replaced and there were plenty other cords to use until the new one came.
My only complaint is the limited size range - they say they will come out with larger sizes but as I knit very loosely, I need smaller sizes.
Over all I think they are the only way to go when you first start to buy needles.