I've used the Arianne with a variety of processors, except the latest Orbans. I haven't used anything of theirs since the 8200.
I've used an Arianne with the 8100 and achieved much better results than with an XT chassis...both had the card 5 inserted. I can compete with today's boxes using that combo.
The analog Arianne is the very best of it's kind...I haven't used their digital sequel...but I can imagine. Arianne provides spectral balance control and allows a final limiter to really stay within a sweet spot. They're uncanny. I never got an Omnia6 to sound the way I wanted with an Arianne...but with the newer software and presets, I'm proud to run Omnia6Exi's barefoot.
The main reason why I would use an Arianne today is for one thing: protection of a digital discrete STL feed from the studio. When we go HD and digital, we'll likely order 2 analog Arianne's, btw.