Several thoughts from a non-collector of bottles:
1. Perfumes have less exposure to air if they remain in their original spray bottles. I would think they'd deteriorate faster if decanted into a splash type container. But of course, some perfumes' original packaging is splash to begin with.
2. If I did decant into a splash container, I'd want the size of the receiving bottle to be in line with the volume of perfume being put in, so that there would not be a lot of head space with air (again, to reduce deterioration.)
I do enjoy looking at blown-glass perfume bottles at craft boutiques, though. I think I like the ones with multiple colors best.