I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
And this is pure AU, given what happens at the end. It's pretty much a fanservice story: wouldn't it be fun to see Green Lanterns, and Red Lanterns, and all the color Lanterns in the Star Trek universe? (Nu!Trek, by the way.)
Even better, we get to see some Star Trek characters as wielders of the rings. Hal Jordon, the first Green Lantern to meet the Star Trek crew, gives a brief description of what the rings are, and what they can do, as much for the crew as the readers who are Trekkies, but not acquainted with the Lanterns. (Honestly, some of this spiel, like the parts about colors being tied to one emotion and how the ring chooses its bearer was good for me: it either refreshed information or gave me information about the colors and how they match up that I didn't know. I was curious, so I looked up the Lantern oaths for different colors, and all the different versions when applicable. It was a fun little rabbit hole, to be honest, and I know officially know more about the Lantern Corps than I did before!)
I'm still confused by the ring question: why can some be taken off others, and Green Lantern rings cannot. Still, this could be something that I don't know about, and it could have to do with willingness to bear the rings, at least of different colors. I mean, I can come up with reasons and I'm barely familiar with this franchise, so maybe I'm making too much of this. I do think that it should have been explained more in the text, but I understand that it was a heat of the moment thing, thus turning it into a catch-22: if any character had stopped in a life or death situation to explain the situation, it would have felt like forced exposition.
The characters were true to themselves, at least the ones I know. Even Jordon, whom I've read about and seen on some shows, seemed in character but someone who is more of a DC fan would be able to speak to that better than I. I assumed everyone was done well on the other side. I know barely anything about Sinestro - bad, bad man, bears a ring, enemy of the Green Lanterns - and that came through. I wouldn't be able to tell you more about his particular character, or characteristics.
The illustrations were gorgeous, with lush colors for all the rings. Again, not so much with the DC side, but I thought everyone was incredibly well illustrated from the Star Trek side of things. I found myself less interested in the art gallery of all the covers at the end, although there were some that really emphasized the crossover in nice, but simple, ways and those covers did catch my attention.
I know the hope is probably futile, but just letting everyone know, I would snap up issues of a sequel to this in a heartbeat.