So, someone mentioned that I should come back here and share my own "thoughts" on the difference between the serenity coated OEC and Amora OEC, after having the Amora in my setting for a couple of days.
Well, here goes. Stats: Both OEC's are 7.5mm. One is enhanced via serenity lab coating (large culet) and the other is an Amora OEC (small culet).
The Serenity Coated OEC is absolutely breathtaking and, IMO, very similar to that of an antique OEC. It's got fire and brilliance like I've never seen before in ANY stone. The large culet is my favorite and not exactly "large". I like to say it's easily detected

Because it's not large in the sense that it's overwhelming in the stone, it just adds this extra kick and beauty. I see grey in the large culet OEC that I do not see in the Amora, when set. That last part about "when set" is extremely important. I feel that my setting seems to make the large culet OEC appear dark. It does not have the same affect on the Amora when set. With the large culet OEC not set at this time, there is absolutely no grey.
The Amora is so diamond like it's crazy! My boss, co-workers, people on the street, etc have all commented on what a beautiful diamond I have

Heeheehee The Amora culet is much smaller than the first batch of OEC's culet. The stone is white, very white but not too white. It also has a ton of fire and brilliance, just not as much as the serenity coated OEC, IMO. I feel that the Amora OEC is a beautiful stone. The "I" color is perfect, for me.
All in all, I will be 100% honest and say that the serenity coated OEC is my favorite. Hands down. However, the Amora seems to be the best fit for my setting. It compliments it very well. It looks almost identical to my friends new Tiffany yet mine has the extra fire, that lovely open culet and the intricate faceting that we all know and most love in the OEC's
I love my original OEC so much and would never dream of parting with it. So for now, I will take KatNewby up on her offer and ask for advice and suggestions on a pendant for my OEC. It would be MUCH appreciated =)
ETA: For those that have not followed this thread from the beginning. My avatar pic has my original large culet OEC set.