I will probably be able to answer this myself once I find somewhere that stocks Blu Notte so I can test it! I have tried Blu pour Homme, liked it but not enough to buy it, and I'm expecting the addition of a dark chocolate note will make it bottleworthy.
The thing is I'm just curious of others opinions on this one.
Evidence I have found that says no - about 15 BN members have got both in their wardrobes (found this out using Google), and rate both as 4 or 5 stars.
Evidence I found that says yes - those that dislike Brit say it smells of Baby Wipes. Those that dislike Blu Notte says it smells of... Baby Wipes.
I have never owned Brit and therefore I can not claim to have worn it for very long, but from what I recall of it and having owned Blv Notte, I do not think owning both is redundant. However, they are both modern, oriental, woody fragrances that share a ginger and floral accord. The difference I see between them is that Brit favors roses and powdery vanilla making it great for day or night wear, where Blv Notte is more tobacco, chocolate and woody towards the end (very velvety) making it more suited for evening wear.
I would definitely sample them both first. Many more people like Brit because its less synthetic smelling.