Yes I agree, I can play 09c on FH all fine, but I didn't like it, and so can anybody that plays H3N indeed. And as I have said many times, not every amateur should do H3N, I have clearly stated why not and why yes (with a word of caution if yes)
As an example, Andy (not his real chinese name), one of our best almost national amateurs, played for his whole life H3 on his penhold taksim. Recently it broke and he bought a D09c and has been playing since with it.
However, because I often train with him, he is not happy. He says he doesn't like how bouncy it is for TPB blocks, and that he has to close the racket more so he misses more and has less feeling. He also indeed complained about the price but also about less tack. He does enjoy the extra power on certain shots and that he does not need to boost. As always, tradeoffs.
But Andy is way above USATT 1800, more like 2200-2300 so he is not the main audience Im addressing with my blogpost.
In any case, to summarise, yes they are both similar, but in my opinion, for most of those who play H3N on FH, and there are many of those in this forum, I do not recommend 09c. They can play it, but won't enjoy it. For people who play tensors and are used to those, I dont think is worth changing to 09c unless they are prepared to adjust, just like with H3N.
For the backhand it makes more sense to use 09c in my opinion and school og thought, but I do not recommend it for most (note, not all) amateurs under the conditions I specified before due to the fact that a cheaper, easier to use and more forgiving rubber is going to be the better in most cases.
So this is my perspective and what I explained in the post. I knew it would be controversial and many would disagree, that's fine, I think its good for others to see the disagreements, plus I enjoy a good verbal discussion as you know from previous times where we differ.
I do hope that now the opinions and perspectivea have been enough clarified