NCRC had three folks (WA1ABI, KA1BQP and WB4SON) participating in the ARRL’s April FMT a few days ago.  The results put all three in the “Green Band” (less than 1 Hz error), and they placed 7th, 12th, and 18th out of the global contestants (John WA1ABI had the top score in RI).  Their results had errors of around 12 parts per billion.  These days the limiting factor is one’s ability (through luck and skill) to divine the influence of Doppler, caused by changes in the ionosphere, which shifts the apparent frequency by 200 parts per billion or more.