I don't even need to finish that particular idiom. It's one I have heard many times during my life - usually by people that have mistakenly taken my expression of interest in something to be a desire to have it.
My answer, if I ever hear that again is going to be "No, it's just a different shade of green".
I loved this visit to Australia. I adored almost everything about the country from flora & fauna through to food & shopping. Without doubt the contrasts within the areas we visited had me spellbound & I didn't want to come home (much less back to shaky ground!!). Heck, I was even enthralled with the rain!! But the point is that I was there as a visitor.
So is the grass greener on the other side of the 'ditch'? No, it's just a different shade of green, but right now I'm still quite enamoured with that particular shade!