What is branded as UAD may as well be bx, Sonnox or whatever.?
My materials always again react differently on different FX - as do I myself. Just tested around Saturation Plugs and ended up liking the Cubase stuff most for my purposes. Softube Harmonics yesterday - try the Transf(ormer) mode. Pretty awesome. Never got "that" (lowend) with Acusticas
But Acustica is permanently on, lately lots of N4. Cupwise CupTone. Timp ColorBoost. Very "efficient".
Convolution [...] can bring you lots of power. Reflections. Tonal Balance. Whatever. Patience and analytic experimentation required.
Analog Obsession FetDrive + FetSnap are the way I make things going, too.
But honestly ... quality is fluid. No day is like the other as are the waveforms of the synths. I just generated sawtooth wavetables of all my synths and you wouldn´t believe how different they are. Taking an other one may be a solution, too. I´d recommend to try the MSoundfactory Generators if you haven´t done that yet. You can always work with harmonics (and much more) if you feel so and the overall quality of the OSC/generators is out of touch.
I have changed my mind, too. I like my well selected plugins but you really have to get familar with them. That is a time consuming passion. And at the end of the day knowledge - even if it is just generated from experiences you have collected - is quiet sure most effective and efficient when it´s about reaching your targets.
"Overall sound" is my passion btw.
