I do not think they are very similar at all... maybe some people are picking up on the pink pepper in both? Violet leaf dominates Libre to me and while it is decent frag I'm not sure I would pay money for it.
The longevity of Libre did surprise me, when I first put it on I didn't think it was going to last long at all, but it lasted a good 2 hours with some projection then the next 2 hours were a good skin scent. I get varied longevity with Bleu, but in no way would ever tell any of my customers that Libre lasts longer than Bleu.
I looked at your wardrobe and if may be so bold to recommend you give CK One Shock a try. Fantastic longevity and projection and very, very economical! Some ppl are turned off by this one right out of the bottle, but the dry down is great! Not too heavy and I think a great frag for your age group and up. I just wore it to work today for the first time in a long time and one tiny little spray (like a half pump) literally projected a good 6 hours on me and 12 hours later now I can still sense it on my skin.
And welcome to Basenotes