aopi or tri sig

Seriously, Tri Sig. Give it up. Let girls decide for themselves. TKE is going to drop you any way.

AOPi.

Both are great choices. Don't let strangers decide something so important for you! Great girls in both chapters.

Tri sig is newer and thus has less girls, they're "lower tier" because they don't have an established reputation on campus. I'm not sure about their sisterhood, but I'm sure as their first "new" pledge class the new members will have a pretty tight bond. Aoii is ranked a little higher and they have a pretty tight sisterhood. Honestly, it's all about where you feel that you fit in best because that's all that's gonna matter. Good luck, hopefully you're happy with your decision and have a great Greek experience :)

If you care about tier, go AOPi just because they're slightly higher plus they're more established on campus.
If you don't, go with the chapter you have had better convos with/ feel more comfortable.
Also, don't pay attention to THON partners... they switch, like, all the time. And if AEPi gets kicked off due to recent allegations and is unable to participate in THON in coming years, their partner (ESA) will likely join with TKE and TKE will leave Tri Sig. So don't pick Tri Sig solely because they're paired with TKE, THON is likely the only interaction they'll ever have with them.
Good luck!