VS2 - I - Comparisons.. What's the difference?

[Markerman]

Hi all,

I am wondering what your eyes can see that I can't in terms of ideal-scopes and ASET images. Looking forward to your expertise!
All of these diamonds are ACAs

Diamond #1 - $4,140 - HCA 1.5
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2813962.htm

Diamond #2 - $4,160 - HCA 1.5
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2813952.htm

Diamond #3 - $4,468 - HCA 1.4
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2792438.htm


A few questions so I can train my own eyes:
1) Although Diamonds #1 and #2 are the same prices - what small differences would make you choose one over the other?
2) Diamonds #2 and #3 are very similar in the amount of inclusions (according to me) and specs - is there anything that would warrant a $300 difference?
3) General question - does it make a difference if in the ASET images, the center is either green or red?
4) Would you consider any of these stones to be worth buying considering their specs and price (ACA premium)?

Thank you all for your insight and in helping me gain more knowledge in these details

Mark