You can't really call this a manga; It would be more accurate to call this a comic. I bought these because I wanted to see the Japanese take on Star Trek; This isn't that. Why call this Star Trek: The Manga if it's not a manga?
This is a collection of short stories all written by Western authors but they are drawn by Japanese illustrators in the manga style. However, the stories read from left-right. They are also more wordy than the average manga, about as wordy as the average Western comic.
As each story is written by a different author, the quality varies from story to story, as you would expect. The quality of the story varies from good to poor with most being average-poor. There are no excellent stories but there are no awful stories either.
The illustrators are all roughly the same quality but they all draw the characters differently. This means with each story, I have te learn which characters are which, which usually takes the first page or two. Although, it's usally easy to pick out Mr. Spock, thanks to his Vulcan ears.
I'd say the characters are, for the most part, similar to their T.V. show counterparts.
I had much more enjoyent from the short stories at the end of each volume (that were there to sell colections of short storys that were coming out at the same time these comics were published) more than the actualy comic stories in the book.