Oooh, Jouf, you have both sets, eh? Just curious, how do they compare? I've never tried the Denise set.
I have an old Boye set from the 60's, in addition to a modern set. It's great to have two sets, because using two circulars is a pleasant way of doing small diameter circular knitting. If I hadn't already accumulated all my DPN's, I'd probably just use the two circulars all the time, to be thrifty. But I do like my DPN's, so I tend to use them. I could see getting used to two circulars, though, it's a nice way to work, too. Of course you can also do ML knitting, and do literally all of your knitting with a single interchangeable set. But I'm not a big fan of ML, personally. Nice to know for when I'm in a pinch, but not my prefered method.
Yvonne, you and I are true Boye-converts. I love my set too. Yes, they are so smooth. I've only used Addi's once, but I definitely didn't knit faster with them! (They were a 16" circular, which don't have as much needle to grab onto--so it might not have been a fair test, compared with the more substantial Boye's. But it did leave me with renewed appreciation for my Boyes!)
I do use the tightening tool, too, but much prefer the rubber-glove material for a grip. I actually bent my little tool thingy, because I got so much torque with that grip! LOL. Maybe that's why they give you one with less grip, for muscle-gals like me! LOL.
Nuno, I'd search around for reviews of that set. Bamboo can have flaws, like Marnie was saying, and you want to make sure it's got a good join, etc.