Its been a clear upgrade for me. I am on T-Mobile and in my apartment i see around 200-300mbps and across Seattle metro area i hit 200mbps consistently.
T-mobile has better coverage here compared to ATT and Verizon because of Mid-band spectrum they got with sprint merger. I think other 2 are in process deploying more mid band spectrum and may be that will improve it in future.
In Seattle I see 5G UC (Marketing term for their MidBand Spectrum) for TMobile pretty much everywhere.