TAS Intern at non-Big 4 vs. Audit Intern at Big 4

Long time lurker, first time poster here.

After 1 year in FP&A at a Fortune 100 doing glorified accounting, I have started a MSA at a top 10 program and am located in the Midwest middle market. I have received 2 offers for this coming spring: TAS at a regional accounting firm and a busy season audit intern at a Big 4. The TAS internship is focused on buy/sell-side due diligence and quality of earnings reports within the middle market industrials space and the audit internship is well... audit. My question is about which one to accept.

If I want to move into TAS/IB/Corp Dev down the road, would it make sense to decline the Big 4 offer for this much smaller firm to get TAS experience and cross my fingers that they give me a return offer? The Big 4 offer would allow me start full-time as a second year and then I could exit after another year into TAS or send some prayers to small MM IB's. Would this Big 4 experience be better to start from since I have seen a lot of TAS roles ask for Big 4 experience as a requirement? I know students fall into the trap of "I'll just transfer within the Big 4", since it can be very hard to move into the different arms of the Big 4. But I have talked to people within Deal Advisory and that is a big interest of mine as well.

I am using my MSA to rebrand my useless Economics degree and figured the risk/reward and cost of an MSF isn't worth it if I can't secure an IB offer. So, I am looking for some pros and cons of each offer and what I might be giving up by accepting one over the other as far as exit opportunities would be. 

Sorry for the ramble but I'm just struggling (albeit, not the worst problem to have) with which one to accept and trying to weigh which offer would set me up better for the future (I do not want to go back to private industry). Anyways, let me know your thoughts and what you've seen from people in similar situations.