Hi! I have J .41/.42 AVC stud earrings. I love them. But since they are always in my ear, I haven't really experienced them in comparison to my E ering. I can tell you this, however... I had Perry source my cushion for my ering and it's the most gorgeous diamond I have ever seen. The faceting and outline shape look just like the stone you posted. If you go for it, I think you'll love it.
Just got my J VS1 1.53ct Octavia Asscher and I absolutely love the colour. It is different in every single light condition - sometimes looks quite yellow, but mostly pretty white. And in the sunshine, well, wow!
I own a J (our jeweler thinks its closer to an I, but GIA says J) colored 8-main square cushion. I love the warmth indoors and have put it next to my friends D in bright sunlight and neither of us could really discern a huge difference (certainly not the kind you'd imagine with 6 grades difference).
I went with size over color, and let me tell you, I'm so glad I did! I love my 2.01ct J RB! My J isn't really warm, but it's more metallic I guess you would say then warm. My studs are Gs and I wish now I would have went with Js and just got bigger stones. But your cushion looks gorgeous. You'll love it!
I have a J round brilliant ideal cut. It has slight warmth but is surprisingly white. I have heard that color shows up less in round brilliant compared to cushion or princess cuts... But I really think cushions look beautiful in warmer tints because they look more antique - if that makes any sense.
My EC is a J, and honestly, the only time I notice any color at all is when I'm in a jewelry store! It looks so yellow in their lighting that I've even had a sales associate ask me if it's a yellow diamond. It's very weird, but any other time, it's white, white, white!