Thanks so much for your help!!The differences are pretty major between the three you mentioned. The new OS compared Bipolar OS is much smoother in the midrange, clearer in the lows, and less harsh in the top end, so it doesn’t hurt as much when you crank it up. It’s a different speaker, different gear, different room, and a much more useful feature set....basically three more years of experience in getting higher quality and better captures between the two.
The OS and Traditional cabs have very different sonic signatures to them. The OS is just BIG... the lows and deeper and it has a little more air on the top end compared to the Trad. The Trad has a tighter low end and is more mid-forward and aggressive IMO. I made a clip at post #90 that compares the two with the same mic position (with a single 57) and same amp and settings to hear the differences between the two.
I ended up getting both the latest Mesa Traditional and OS cab bundles and wooooow, they are both really different, and really good. I've been using Mix 01 from the Traditional cab the most lately - I've found it's pretty much perfect whenever I wanna take a solid rhythm tone and make it sound meaner and angrier - I think I actually yelled "OHHHH!" at the screen when I started trying it out on some of my presets (so far, I've tried it out with a Mark IIC++, a Diezel VH4, a 5153 100W Blue, and a 5150 Block Letter). Interestingly enough, I've found that a lot of presets tailored for a blend of the 4x12 Recto ST 57M C YA + 4x12 Recto ST 121 Brt YA stock cabs from your old Bipolar bundle (aka the Leon Todd special) sound incredible with Mix 01, with few or no tweaks. Phew, I've gotta catch my breath now