This is very intriguing to me. I was just reading their white paper on tax loss harvesting. After doing my taxes this year, I was seriously considering going with them just for the TLH. I didn't like the extra fee they charge, cause I can beat it, but the TLH would have been worth it.
Could you share which funds are in your 403b? It would help people like me figure out if this will apply in our case.