For me, as of today:
20% niche 80% Mainstream
Mainly because I've been here for just a few months so I'm still discovering the different niche houses. After some intensive sampling, I've come up with a "what to buy next" list -- which is 80% niche 20% mainstream. So at a rate of three bottles a month... In a year, it will be approximately -- [50% niche, 50% mainstream]
Come to think of it, I am not impressed by a lot of the niche houses' offerings. (Especially MPG, 06130, Montale, and Creed) Despite being well made, using "quality" ingredients, etc -- they're just not what I'm looking for.
I am a big fan of boozy scents and woody/spicy/incense types. I also enjoy the "amber" accord -- with SL's offering being a personal favorite. There is an absence of good "amber" frags in the mainstream IMO.
I really do not pay much attention to the distinction between Niche v. Mainstream -- but prefer to evaluate the scents alone. I do not view niche as being always superior. HOWEVER, I find that mainstream houses most of the time does not offer what I'm looking for -- so I guess I am kinda tired of mainstream fragrances and want something different. What I am looking for in the mainstream -- I have already bought and attained.
As for luxuriousness, there's no denying that packages like By Kilian's ARE indeed luxurious -- but that isn't the lone factor for my purchases. I appreciate a good luxurious package -- but it's the juice inside that counts.
Price price price. Now that's an important factor. As much as I'd love to go out right now to buy Duro, Absinthe, and MoslBuddJewHinDao together for $600 -- that isn't going to happen. I'd have to slowly save up. Where on the other hand, I could get 3 decent frags that are availible at the discounter for a price of $100 combined. But these days -- is decent what I'm looking for? Is it what you are looking for?
The answer -- no. I am looking for the best, which are simply -- the things that I enjoy and find truly intoxicating.
In the end -- it comes down to quality over quantity.