One thing to add to the performance of the ECM is that it latched onto height falls over the GOMEX well ahead of the GFS. From my SAT 5/26 AFD...

"THU-SAT...MED RANGE MODEL GUIDANCE SUGGESTS AN INCREASING CHANCE FOR
A MUCH NEEDED WIDESPREAD/HIGH COVERAGE RAIN EVENT LATE NEXT WEEK AS
WE HEAD INTO JUNE. CONTINUED AMPLIFICATION OF THE WEAK SRN STREAM
TROUGH IS PROGGED TO OCCUR OVER THE GOMEX BY BOTH THE 00Z ECM AND
12Z GFS. ECM IS MUCH MORE ROBUST WITH BOTH THE H50 TROUGH...AND THE
SURFACE RESPONSE...HOWEVER BOTH SOLNS SHOW ENOUGH AMPLITUDE TO ALLOW
DEEP LYR FLOW TO ACQUIRE SIGNIF SRLY COMPONENT TO ADVECT DEEP
TROPICAL MOISTURE NWD INTO FL. BY FRI/SAT...THE ECM SHOWS A MORE
CUTOFF/SLOWER SOLN...WHILE THE GFS LINKS THIS WEAKNESS UP WITH THE
NRN STREAM...CREATING A BROADER MORE FULL LATITUDE TROUGH. IT'S
HARD TO IGNORE THAT THE GFS HAS OFTEN FOLLOWED THE ECM'S LEAD WITH
THE CURRENT PATTERN...AND IT IS ENCOURAGING TO SEE BETTER AGREEMENT
BTWN THE TWO...THOUGH IT STILL IS IN THE DAY 4+ TIME FRAME."

Additionally, I distinctly remember much stronger height falls working toward the GOMEX on the H144/H168 panels of the FRI 5/25/12Z run of the ECMWF compared to the corresponding run of the GFS...hence the "IT IS ENCOURAGING TO SEE BETTER AGREEMENT BTWN THE TWO" comment from this AFD, issued the following day. More kudos for the ECM, which is usually the stellar performer amongst the globals in its depiction of the H50 height fields over NOAM/CONUS.