SEC for many reasons (in no particular order):
1) It is the best football conference;
2) It would help recruiting the most;
3) We have not played well in cold weather in the past (only our greatest teams were seemingly unaffected by weather; our less-than-stellar teams were heavily affected by it). Could you imagine a bunch of SoFla divas going to Indiana or Purdue (basically bfe) and it's December and their W-L is say 5-4 and they are not really that into it? We've seen that movie before in the El Paso bowl & others and it ain't pretty;
4) There are very few appealing destinations to travel to in the BIG (outside of USC & UCLA). Games against Purdue, Northwestern, Indiana, Butgers in winter in really cold & depressing places etc. Nah...thanks, dawg;
5) Attendance & atmosphere at HRS would see a major boon from joining the SEC. The SEC would travel well for virtually all of their games. That would leave only OOC games against weak opponents at risk of poor attendance. Virtually all other games at HRS would be sold out...and we could sell that on the recruiting trail;
6) Almost every game against an SEC opponent would be of interest to me. Only a handful of games would be in the BIG.
7) Our strength of schedule metrics would be off the charts in all 3 major sports;
8) Our South Florida athletes (fast, explosive, athletic) fit better in the SEC than in the BIG where it's slower, larger and more lumbering players. Remember when Golden tried to "BIG" us in recruiting? It wasn't a fit. Also, it's been feast or famine for us against big physical run-oriented teams like Wisconsin. When elite, we've destroyed teams that were one-dimensional. At other times, they've run a train on us and we could not stop it. How miserable would that be to travel to Wisky in December and sit there in the freezing cold and watch them pound the ball down our throats for 3 hours (note: this won't happen under Mario because the trenches are getting a HUGE upgrade on both sides but it could happen post-Mario in 20 years);
9) When we were elite in the late 80s, we dominated SEC teams like LSU and Missouri by scores like 44-3 (in Baton Rouge no less). Yes, the SEC is more likely to control our fate than the BIG but if we're great there's only so much the refs & the Commissioner can do (in the NIL era). Pre-NIL it would have been a whole different story as the only sacred cows were the current top 5 schools;
10) Games against UF & FSU would be great (assuming FSU also joins);
11) Travel for football isn't that big of a deal because of the limited number of away games each year. Travel for Baseball and Basketball (and non-revenue sports) could be a real burden in the BIG as Baseball plays quite a few games;
12) Can't stand OSU and don't want to be reminded of the tainted Fiasco Bowl every year; and
13) Vandy's a prestigious school academically and it hasn't been hurt by SEC membership.
We fit much better in the SEC in almost every aspect. Two other big factors to consider are: (i) revenue & payouts and (ii) research grants.