Both the SOM and STL proposals feel New Yorkish to me, but that isn't a problem IMO. As much as we get into pissing contests, our two cities have an extremely similar architectural tradition rooted in sheer capitalism.
At least they don't look like something from Dubai or China.
I honestly don't know which one I prefer. Both are excellent designs, the STL with its taper has a superficial resemblance to Hudson Yards or Manhattan West if you squint but that's where the similarities end. The white cladding is beautiful, reminds me of Alvar Aalto. But SOM's terra cotta will also be stunning so
I'm still worried the SOM cladding is too costly and elaborate, I'm worried about some major VE; we couldn't even get a proper curtain wall on Vista, what are the chances for this one? But VE could also happen to the STL design and we end up with a boring-ass white window wall.
The SOM proposal is also a lot more nostalgic with lots of references or straight borrowing from Art Deco, while this is more pure and Modernist. I do think the base is stronger on the STL, it beckons people to walk through to DuSable Park while the SOM's base is like an urban box canyon, just a clear visual dead-end.
Choosing between these two designs is a good choice to have to make.