The green blend in, the blue stand out. It’s a pretty busy (& awesome) fabric already so I vote green.
Cute shirt! I vote green!
I vote green also. (Cute fabric!)
Swimming upstream, I vote for blue. The square buttons compliment the robots.
I had the same response as @steiconi . And I was surprised that people thought the blue stood out more, for me the green stood out more, I think because of the shape and sheen.
I vote green. I agree with @Magpie. The fabric is busy and the green doesn’t compete with those fabulous robots.
@Tea I was thinking the top stitching was less than fantastic. A compromise, as I stitched all the way around, hem, collar, fronts, and so the visible stitching on the collar is from the RIGHT side, but the visisble stitching on the fronts is the WRONG side, and even though it’s Bernina, the bobbin side is not quite as perfect as the needle side.
Hmm. Would you consider back stitching in the ditch where the collar attaches so you could top stitch the front from the right side? Not that anyone but you would ever notice either way, it looks fantastic. Do you use a foot or just trust yourself to edge stitch evenly?
Green! 
I abandoned both the green and blue buttons and used grey instead. I dumped out one of my BIG jars and found I had enough of these.
About the top stitching…I decided that backstitching and switching at the top had the potential to be more noticeable than the “wrong side” stitches. I used my blind hem foot which has a conveniently placed edge guide.
Good choice, looks well matched.
Those blue buttons deserve to be fearured somewhere, they are really lovely.
I believe I scavenged those blue buttons off a junky sweater. Our thrift store has a $1 rack and sometimes I buy any items with nice buttons, save the buttons and (with only a little guilt) throw away the garments. Generally the $1 items are either damaged or truly hideous, so I figure they would have ended up in the trash anyway.
ha ha I do like the gray buttons as well…and I agree that those blue ones need to be shown off better!
I have a …few…quarts…of buttons.
This is brown, metal and coat buttons, black and gray, little white, and big white.
And a few more in half pints: blue, novelty, boring standard white shirt, red and orange, (tin cup with stray game pieces and miscellaneous tiny toys), green and interesting brown, fancy, (pincushion), fancy sets on cards in the blue pyrex, (my mother’s silver baby cup, fray check), pink and purple, (silk thread and glue stick).
I sorted all of my buttons by color during Covid and put them in jars. It took less time than you would think, even with this many buttons!
Impressive! Also, I love that tin toy sewing machine and the Scooby Doo Mystery Machine.
@endymion My husband found my unicorn this year–the Scooby Doo Mystery Machine alarm clock. I display it proudly in my sewing room.