Hi meep,
I was waitlisted at TC: I've also read some things online about the administration not being very personal, but not specifically in the SLP program. I would recommend getting in touch with the school directly and asking if you can speak to a current student about the program: they are going to know the most about the how the program is run and what to expect.
In terms of building connections and the prestige associated with Columbia, I'm not saying a "name school" won't get you a coveted job over some one else, but at the end of the day, clinicians who graduate from ASHA certified programs are pretty much guaranteed work after graduation.
There is a lot to consider. Best of luck!