I have a Synergy setup too, but don't have those modules. Though they are on my list to try. What partially led me down the hole was pondering saving up for the actual amp(s) instead and if a Uber Ultra and Recto covered similar ground.
I'm more of a Marshall guy. Even though I love the sound, I have a harder time getting a tone that sounds right from a Recto. That flubby low end is harder for me to work with. My ears hear the Uber Ultra as in the same general ballpark with tighter low end and much more modern sounding. I think it's the low-mids that put them in a similar realm for me. I think I'd have an easier time working with a Uberschall than a Recto. And of course where does a modded Recto fall in?
Even though I'm more of a Marshall person I would like to have other tones available. I don't want a wall of M-style amps where the differences are so nuanced they sound nearly identical. I also don't want to spend a fortune on an amp that might just sit there unused 90% of the time. Maybe I should just start off with the Synergy modules of each and go from there.