I don't know. I've only played Mass Effect 3 twice, and the first time without the DLC, so I can't remember everything about it. However, I've always seen it as my favorite game in the series. I think this is because, unlike 95% of the people who played it, I saw the entirety of the game as its ending. I was so amazed by how many threads the game tied together and payed off, that by the time I got to the ending, I honestly didn't give a fuck about the Reapers. That said, the first time I played it, I loved the ending. Why? Because (1) it suprised me, (2) it was really, really fucking dark, and (3) it left a massive amount to interpretation. The reapers were such an ominous and inhuman enemy, that their motives always need to be left a bit vague. I liked the original ME3 ending, because it didn't over explain anything.
When I played ME3 a second time, the redone ending had been released and I recall hating it. They made it very difficult for anyone to die (When I played the first time, the original release had a bug where your entire team dies rushing the teleporter, regardless of what you do, which I loved because it was a massive gut punch and fit with the suicide mission tone the game was building), and they overexplained everything, which collapsed it all into absurdity. In the original, the synthesis ending worked for me because they kept it vague. Is synthesis a metaphysical idea? A shift in perspective? A sort of Hegelian dialectical process that's ongoing? You could interpret it in multiple ways. I interpreted the final shot of EDI and Joker emerging from the wreck on the planet to be the "synthesis," with their union restarting a new race, almost Adam & Eve like.
However, in the redone ending, synthesis is shown to be a massive wave of energy that gives organics, synthetic bits, and synthetics, organic bits. Which is just fucking retarded. It smacks of some suit panicking and saying, "Oh shit, they completely hated our vague and abstract ending, we need to make it as literal as possible ASAP." I think I'm the only person in existence who liked ME3's ending better than the redone ending. I know some people dislike both, but the original genuinely was objectively better in many ways.
All that said, I'm excited to replay ME3 because I genuinely cannot remember huge chunks of it, especially the stuff from the DLC, so my opinions may change entirely once I replay it.