Rapture Pro vs Omnisphere 2......especially with system resource usage

I can't answer either of your 2 questions, but it responds well to my WX5. I also had good results with Fabfilters Twin 2, setting response to the breath controller across a number of modulation destinations was a doddle. I was running it in demo mode, but will purchase when I finally see in a sale for the right price.

Have you worked with the original Rapture at all? I found the pads to be very nice, at least equal to the ones that you could obtain from Albino 3 and/or Blue (just for example).  Once you dig into the guts of the interface, the synth engine is extremely powerful with a lot of modulation options.
 
The above being said, I've not yet tried Rapture Pro.  It's on my to-do list.

I think I'm asking different questions from a synth than someone looking for big leads. I was referenced it due to the use of breath controller. This is implemented well in Rapture and even better in Twin, it's awful in AAS Ultra Analog.
 
I don't know about how modulations are dealt with in O2, having never tried it. Clearly O2 looks immense as a synth.  

I'm with Maddcow saying he's a Windcontroller player, he's using a midi sax, rather than a keyboard with a breath controller attached.
 
This is what I use and have for over a decade I think, I don't own a keyboard.

 
It's a very different way of plying midi to my mind, because it's forced to be monophonic, it means breath modulation is always synced to the note you play, and shaping the one note. I hdon't own any virtual orchestral stuff, so have never tried. But I imagine it would work very well, especially for wind a brass, it does with synths that allow breath routing to be controlled well. The breath controller aspect is very responsive.
 
Being not a keyboard player, I'm not sure how natural it would feel blowing into a Breath controller whilst playing keys. For what i've seen posted about it though, people that have them are big fans of them. I think it would be shaping the sound in a different way than with a Wind Controller (as opposed to breath) because you'd can shape clusters of notes. And where I play staccato, the breath controller modulation will fall to zero between notses, with a breath controller on a keyboard, you can keep moving the modulation even when nothing is played.
 
So they are a bit different in applications, but breath control modulation is a powerful option.

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