I'd like to murder whoever invented this word (I'm not gonna use it: I'll use "Out Of Focus Areas" instead OOFA!). I never heard it back 'in the day' and only heard of it around 2010 or later (maybe I'd heard it but didn't pay attention). Yes, some lenses and techniques produce nicer out of focus than others and it seems that mostly that's due to the number of aperture blades a lens has.
I have lots of old cameras and most of the old ones have 8/10/12 aperture blades. Shooting them, I note that even my 1950's Super Paxette produces smoother OOFA than my lenses from the 80's and 90's. It seems that manufacturers reduced the number of blades, probably to reduce cost, and some even had systems to create smoother OOFA.
My Minolta A7 film camera for instance, has a special mode, STF or “smooth trans focus”. I used to have the actual STF lens but didn't use it much. The camera achieves this '“smooth trans focus” by taking seven exposures on a single frame at varying apertures creating a 'nicer' OOFA.
Perhaps this indicates the evolution of the word I won't use. The A7 was one of the last high end 35mm camera designs before digital took over.
Many people looking at the camera would think it IS digital with its big rear screen (for setting controls etc).
Anyway, I've improved the quality of my lenses over the years, trading cheap lenses for better glass (from alt brands to Minolta and Zeiss). I use OOFA constantly to isolate the subject from the background and it's the isolation that grabs me, not the shape of the OOFA. Yes, some of my lenses make bubbles, one makes doughnuts, others just make smooth OOFA. I don't usually choose my lens for the OOFA though, I choose it to suit the shot.
About the only time I deliberately choose a lens for it's OOFA is when I'm shooting sports with a long lens. My 500mm Minolta f8 mirror lens is handy but on bright days, it's OOFA is the unusual looking doughnut shape. That can be distracting so, in those cases, I'll sacrifice 100mm and use my Minolta 100-400mm zoom which has a wider aperture as a bonus.
Outside of 35mm, most systems don't offer lenses with different OOFA I love my Fujica G690 and have 4 lenses for it: 50mm, 65mm, 100mm and 180mm. Fuji only made one other lens for it, the 150mm, and no alt brand ever made a lens for it. However, that doesn't matter; it creates stunning images if and when my brain creates them first.
I'd never pay OTT prices for an OOFA aperture unless the glass and build itself were the reason for my purchase (ie. Zeiss from Sony digital fits my A7 and I have two). So for the finale: I shoot great images sometimes but they are not great images because of the OOFA, they are great images because my mind saw something I could 'exploit' by composing and exposing the shot in a creative way.