No problem!
The Stellar and Lexi have a british style crunch in the way that they clip. Smooth and musical. The Americana has a fuller low end top end chime(think blackface amps) and touch "looser" feel to the break up.
The Stellar is the most organic out of the 3. It has a hint of grit that is always there. It's what makes the Stellar special and gives it a pseduo fuzzy character when completely dimed. The Stellar is openly voiced and has a terrific gain range. It was designed back when I only played tele's. It sounds great with humbuckers/p90s too, but in my heart its a match made in heaven with a telecaster.
The Lexi is more compressed and not as open sounding as the Stellar, but also isn't as gritty on lower settings. The tone knob is a more of a cut knob than anything, so it is the least versatile tone section in any of ourpedals, but it does exactly what it needs to do in that particular pedal. I personally think the Lexi sounds best on amps that are allowed to "breathe" aka be turned up a louder than bedroom level. This honestly would apply to any pedal but YMMV
The Americana is one of my favorite "other" overdrives to use. It is a very full sounding overdrive. I use mine more as a preamp tone shaper. It fills out single coils very nicely and makes my SG chimey as well. The break up is just different on it, but in a cool fender/ampeg esqe kind of way. The Americana always seems to fit the bill when my British drives are not fitting the vibe.
Hopefully those descriptions somewhat make sense. That is all just my personal experience in my rig.
Im im allowed to be biased for a moment...
If i lived in a world where I could only have one overdrive, (what a terrible world...) I would pick the Stellar Drive.
Like i said your best bet would be to try a few out in your rig, including the OCD. What works for me may not work for you.
best of luck with your decisions!![]()