I use Fidelity almost exclusively for taxable and retirement accounts (through work) but my mom's retirement is with TIAA. WHen I help her with managing her accounts, I am always very annoyed by TIAA, both because their website is much worse than Fidelity's but also because her investmnet choices all have high-ish expenses. Fidelity has funds that have expenses that are the same or even lower than Vanguard.
So my suggestion would be Fidelity, but as others say, it pays to check the funds which will be available to you and their expenses.