We have about $1M in retirement investments with TIAA-CREF. I agree that they are in the top tier, so to speak, of places you could have your money. Absolutely max out your 403B, including catch up contributions when you are of age.
A couple of suggestions:
(1) If you don't have one already, open a brokerage window in your TIAA-CREF retirement account. This will immediately increase a thousand-fold the options you have to hold in your accounts, including individual stocks, and funds from other fund families. You can hold many other firms' instruments for no added fees (other than the initial exchange fee, which is pocket change.)
(2) If you have retirement assets of at least $500K, consider getting a free wealth management advisor. You never give them discretion to move your money around, and since they are employed by TIAA you never get charged fees for their services (not hidden, they really are free). We've found this helpful with asset allocation decisions. And, frankly.... I get real tired of phone trees and automated systems when I have paperwork that needs to be processed. My advisor and the people in the office have been tremendously helpful with that stuff -- particularly when moving funds over (like to do a megabackdoor roth).
(3) Although there are one time trading fees, you can hold Vanguard within a brokerage window at TIAA.
(4) They have great online tools. I regularly read their articles. And I use their 360 degree financial view tool.
(5) I like consistency. I like knowing that when I start getting my money out I will have some help. And I like knowing I can deal with a person I know. But, I wouldn't pay for it...