Craig Calcaterra gets to the Mets on his comprehensive list of each team’s best and worst uniforms of all time. I pretty much agree with everything he’s got here, but he neglected to mention the epic 1997 white-hat experiment (which I still prefer to the black hats).
Tedquarters
Ted Berg
Tedquarters 
I was always partial to the 1969-era road gray uniforms. But I’m old school like that.
There was no greater disaster in Mets uniform history than the Mercury Mets.
http://metsguyinmichigan.blogspot.com/2007/05/glorious-disaster-that-was-mercury-mets.html
The black uniforms are a very close second.