I was very happy when Fidelity added HSA. Much better than the 2 previous places I had HSA. Fidelity HSA just works, and is directly investable, including in the very competitive iShares index ETFs.

I wish more startups would find a way to use Fidelity or Vanguard (with access to the very-low-ER index funds).

I never did figure out how to track Guideline 401k in GnuCash satisfactorily. It was complex, when all I wanted was a balance of IVV/ITOT and AGG (or Vanguard equivalents).

And a different startup used Transamerica 401k, which looked like it had been forgotten on one person's desk in the basement of their skyscraper a decade earlier, and I didn't like their funds. As soon as I could rollover to an old Fidelity account, I did so.