Where people are concerned, there will always be distortions of "the truth." The question becomes, how greatly does a person's purported truth deviate from what's really true? When multiple people give their perspectives and there ends up being a congruity between what most people say, it's a fair bet that the intersection is about as close to the truth as you'll get, given how everybody outside the "event horizon" can only rely on interpretations.
As Christopher said, Solow and Justman relayed a lot of their observations backed by documentation. People like George Takei had no evidence, only hearsay. And overall, what Nimoy has tended to relay seems to fall within the Solow/Justman recollections, so he seems to be one of the more believable cast members. The rest who are still living have their own agendas and some are well known to have gradually altered their recollections in favor of versions that raise their positions.
Gene made a lot of mistakes and showed callous chauvinistic qualities above norm for someone of his station at that time. While he created and envisioned Star Trek, some of the things he did may have inadvertently helped pitch it over the edge to be canceled after 3 seasons. When you look at how Gene's involvement with TNG significantly dropped off into Season 2, it coincides with a shift in the series towards something better. I personally feel the series would've had an even better start if Gene hadn't been so intimately involved. He didn't even want Patrick Stewart after his first interview with him!
Here's what Justman said about Roddenberry's resistance to Stewart:
I was hot to trot. I was very, very enthused about Patrick playing the role. And I kept after Gene and Gene kept fighting me off until one day we had a new producer come on the scene, and that was Rick [Berman]. Rick saw Patrickís film and fell in love with him. As did our casting director. So the three of us were allied in the fight to get Patrick as the captain. And Gene was allied in his own fight not to have him at all. So finally I realised that the more I pushed, the more he dug his heels in.
I made an announcement, one day, in a meeting when the subject was brought up and I said I donít want to hear the name Patrick Stewart ever again. Itís over with Patrick Stewart, forget him. I did that on purpose to make Gene think that Iíd given up.
I think that's very telling. And yet, Stewart was the best casting choice of the whole TNG series.