Thank you for the replies, folks.
I am interested in CPI-U adjusted SPIA and want to make sure there are no caps on CPI-U increases or what happens if the index goes away.
I plan to buy directly from a company or via Vanguard / Fidelity, and when I had asked Vanguard, they said I would only get the contract after signing up.
Perhaps, it's sufficient that I review it myself but wanted to see if you would recommend someone else to do so.
P.S. Currently, I only know of AIG, Principal Financial, and CMFG Life offering these products to folks under 50, so my choice is slim as to which ones to choose.