I watched both the movies last weekend, and I think I finally figured out why it is I slightly prefer GB2. I always liked it better as a child, anyway, because the humour is more accessible (digging a big hole in the street, "once time I turned into a dog and they helped me", and stuff like that) - I'm sure, making the sequel, they were bearing kids in mind more after the success of RGB. It took me until quite recently to see the hilarity of some jokes in GB1 such as the interest on Ray's re-mortgage, and the unexplained underwater mass sponge vibration.
So that was why I preferred GB2 when I was younger, but I haven't changed my mind since then. Generally, I still find it more accessible. Even I know the Statue of Liberty when I see it. Call it a re-hash of Mr Staypuft if you like, but personally, I'm not sorry they did it because I appreciate it so much more. Similarly, I knew plenty about the Titanic as a kid, and now I know that little bit more about it. It's something we all know a little about, and even an actual link between my little world and the Ghostbusters' (in terms of the movie, anyway), so that's something I've always enjoyed.
I prefer Vigo as a villain, because we get to know him a little bit throughout the movie, whereas Gozer doesn't even make an appearance until the climax. I always used to enjoy Peter MacNicol's performance, and since I was little I've become a full-blown fan of his after seeing him in Bean
and Addams Family Values
several times. He does have a similar role to Louis in GB1, but personally I find the whole idea more engaging with Janozs and Vigo than with Louis and Gozer et al.
As a kid, I enjoyed Louis's performance in the courtroom, and then pretty much lost interest in him after that. Shippers will be glad to hear that I was never particularly interested in his relationship with Janine, even before I quite understood what it really meant. I don't have a problem with Louis putting on a flight suit and proton pack, because that always struck me as nothing more than a joke at his expense - after all, it's not as though he actually did anything, despite how things appeared from outside the museum.
I do appreciate much more now that what they did to Janine's character wasn't good. Please don't anyone jump down my throat, especially as it was my brother who suggested this to me (honest!), but it seems that her look was an attempt to make her appear more like the Janine of RGB for us kids. I'm not saying it was a successful attempt - it was just an attempt, and it would have had little or nothing to do with the script, which wasn't great for her. I always did enjoy "Typical", and I thought "Well just don't go in there" was a good line for her too. But that's all, really. Still, it's not enough to stop me from preferring GB2 overall.
I've probably mentioned this before, but I was clever enough to see GB2 before GB1 (and RGB before both of them). Possibly that has some bearing on my opinions, but I doubt it, especially as I've seen both movies several times since then and have all but forgotten my first impressions. But it still took me until last weekend to figure out all of the above.