I can see how the Avatar is more user friendly as that is the real weakness of the jd in my opinion. My question though is why you think the Avatar closed the slot better and worked in more adverse conditions when in all honesty the opener looks an identical copy.
It's the same principle/layout of components in the coulter but it's certainly not "identical" - the disc is bigger diameter, the gutler is bigger and heavier, the firming wheel a different size, the gauge wheel is narrower and more open so seems to attract less mud in wet spots, the seed boot is held against the disc very different way and again a different shape etc.
Which of those things makes the difference on our soil I don't know but it's, without doubt, doing a better job than the 750a would have in the same situation as we have right now - that's not saying our 750a wasn't good (it was great for us!) this just seems even better
Only real criticism so far is depth adjustment needs a spanner so takes longer and in a wet spot there is a lot of weight on those seed cart tyres when you are not using it on the coulters. Also the toolbar outer wheels can scuff up soil when you turn tight. none of these things are big deals though really