I freaked out when I heard that Helix 3.10 had a tape saturation effect with Retro Reel. Doing a lot of home studio recording, more often than not I would add a tape saturation plugin to guitar tracks. Tape plugins bring a nice "3D" quality to digital tracks. I've been wanting an effect like that in the Helix for sometime now. To the point I was considering buying a JHS Color Box to put in the chain somehow.
The Retro Reel is an exciting development.
In my findings briefly testing it out, if you use the Saturation subtly it pronouncedly raises the mids. I'm not one for super scooped mids, but additional controls in the effect for that frequency would be nice. I like that includes selectable tape speeds 7.5,15, and 30 IPS. That shows Line 6 was interested in the nuances of tape effects. I'll have to do more experimenting with the relation of saturation and textures levels to each other, and see if I can find a magical combination.
With it being listed as a modulation effect, I don't know if Line 6 made it for the exact purpose I use tape plugins, but I'm excited to experiment and see if I could make it a nice "Pixy dust" finisher at the end of the chain.