My 401k, which is still at my employer I retired from a year ago, was with MassMutual for many years until being acquired by Empower in early 2021. I am very pleased with the customer service I receive from Empower. I can’t say how it compares to the old MassMutual, since I never did anything but contribute and make my own investment decisions before they were acquired by Empower. Personal Capital, which I believe quite a few people on this forum use (at least the free part), is also part of Empower. I recently requested a small distribution using the rule of 55, and Empower made it very convenient to do.