The proportions is good and the price is fair. Not sure about cut quality. Can you view the actual diamond? If yes, try to look at the arrows from the top view using a Hearts and Arrows scope. Also, try to look at the diamond under different lighting.

Since this is an SI2 stone with feather, it is always best that the seller who sell you this diamond sets the diamond for you too. With this, they will be accountable for anything bad that can happen.

Looks very eye clean to me even at such magnification. Besides, ZCOVA is providing the setting, so I won't be worry too much about it. Of course, you can ask for a few more options to compare, and at the same time, shortlist this one first.

I am sure you can find similar 4Cs or even cut at competitive prices at Tomei and Wah Chan, but my guess is that your chances may be slimmer as they their inventory is smaller than ZCOVA's extensive virtual inventory. Wah Chan seems to throw a pretty good deal especially during stock clearance. But to be able to view so many diamonds at high magnification, ZCOVA will be the better choice. And ZCOVA's branding is more posh and luxurious as well. If that stone is chosen by Zi Yin, their co-founder and in-house GIA Graduate Gemologist, then I am certainly comfortable about it.

And Love & Co prices should be higher. Unless they carry those diamonds from some lesser known labs, which I won't encourage personally.

You can try The Gem Tribe and Tailored Jewel and see what they have in-stores for you. Facebook them.