BS blooming size is always preferred by me. I always think that in the worse case scenario, I am within 2 grow cycles from seeing flowers, if not sooner!
NBS is a very misapplied term in my experience especially buying on line!!! People tend to exaggerate and use NBS way too much. BUT in person, with enough experience, you should be able to tell whether or not something is BS or NBS or just plain "BS"!!! 🐂🐄🐂
At the moment I am very confident let's say with Phalaenopsis. I know that I am doing well with those and 'those babies' are going to bloom for me quickly!
Take Bulbophyllums. They are growing well for me too, but I am anxiously waiting to see blooms because I lack sufficient experience to be more confident in my predictions.
A great many people choose the larger plant on a sales table, and that often works. Honestly I don't!!! I look for the plant with the thickest leaves, the Cattleya putting out loads of roots and multiple growths at the same time!! I feel that those babies are just itching to grow well if given good culture! Or I by plants with rounder leaves, thicker bulbs, etc. Many people believe that to be a sign of polyploidy, and that is a killer notion in picking the better plants. And I agree!!
Oh oh, I forgot this. When it comes to species I don't think that "species sized plants deserve a category Ted. Sticking with Cattleyas, I have had Cattleya skinneri, Cattleya bowringiana bloom in 3" pots with smaller growths. But with Catts, I love those plants with thicker pseudobulbs, thicker, rounder leaves, fabulous roots, etc.!!!! I just think that those plants, regardless of genera are just looking to bust out and to grow very well.
With bowringiana, as it grows bigger and bigger it makes more growths and more flowers. So technically a 3", 4", or 8" pot are blooming sized plants.