Issue 18 of the main series was pretty good. I have to say, it was pretty gutsy of the comics to outright introduce a love interest for Celestia, even if it was mostly in the past and with an alternate reality character. The original version of this issue was rejected by Hasbro, according to Katie Cook, and I can't imagine what she could have tried that was even bigger than that. I actually do think this does good things for Celestia, showing that she did indeed develop to become the person she is today, and it isn't really an example of making a female character weaker by making her interested in romance, because it was in the past and won't take over future stories. Concerning continuity, Andy Price stated that Hasbro outright told him that the comics are in continuity until contradicted by the show, which is just what fans have been assuming until now. On that note, this issue contains the Elements of Harmony, which creates the odd situation that this story arc actually takes place before the previous Bookworm arc, which takes place after "Power Ponies".
Katie Cook was saying that they had to fit a lot of things in the four issues of this arc, and you can tell with this issue. It was almost entirely set-up, yet most of it was completely necessary. It does lead to the fact that everyone has disappointingly short reactions to all of the differences of the alternate world, though. That said, it was great seeing things like Trixie as an alicorn representing humility and Flim and Flam representing fairness. Not much can be said about Alternate Sombra's personality yet, but his design is decent enough. At first I was a bit annoyed by the reactions to him, but I suppose it's good that only two of the girls actually seemed to be smitten by him, and the others were just surprised. It was odd to see Fluttershy among the ones smitten, but I suppose there is precedent in the comics with her blushing when held by Hoofbeard in the pirate arc.
We didn't see too much of alternate Celestia and Luna (Fauxlestia and Twona), but they seem like fun characters. I did think the "huring Fauxlestia hurts Celestia" thing was a cheap way to stop the girls from just fighting them right then and doesn't really make much sense as being due to a paradox, but maybe it will be explained more later.
Back on the normal side, it was nice to see Luna get angry at Celestia and Celestia be apologetic. It was also a nice character moment for Luna to look forward to beating up the evil alternate Celestia. I didn't really like how they were written out of directly affecting the other world, though. Also, though it may come up later, after the first issue had all of that stuff with Twilight being unsure about her path, it was a bit disappointing not to see any of that in this issue, but then again, I suppose she wasn't told that her alternate self is a regular unicorn yet and didn't see the picture the guards had.
Overall, I thought the first issue was probably more interesting, but this was still a good one.