Highly underrated in my honest opinion. I grew up with this film. I didn't grow up watching a lot of the Toho Godzilla films (as a kid, "Jurassic Park" and "The Lost World: Jurassic Park" influenced me a lot more). That's one reason why I gravitated towards "Godzilla 1998," mainly because I for one actually DO like & enjoy the fact that the titular monster is portrayed as a mortal animal. That type of characterization of the titular monster appealed to two big interests of mine: paleontology (dinosaurs), and zoology (animals). In short, unlike a lot of people, since I'm not a die-hard Godzilla purist, I'm more open-minded and positive towards the animalistic characterization of "Godzilla 1998's" monster. Sure, it does more or less disregard everything we've come to know and love about the original Big G. So if you're an ultra-hardcore Godzilla/Kaiju fan, chances are, you might understandably perceive this film in a 'It completely disrespects the source material!' light. But, if you look at it as its own stand-alone monster flick (even with the title), chances are your perception will be more positive.
I also truly and honestly like all the human characters in 1998. Seriously, they all come across to me as developed human beings with actual goals and relationships and whatnot. Matthew Broderick's Nick Tatopolous I can personally relate to, with me being something of a nerd who's socially awkward and I good & knowledgeable about what he studies. The highly unappreciated Maria Pittilo I feel gives an emotive, evolving, charming performance as Audrey Timmonds. I found myself laughing with Hank Azaria's Victor "Animal" Piloti and his wife, Lucy. I even how Kevin Dunn, Harry Shearer, Doug Savant, etc. portrayed characters like Col. Hicks, Mayor Ebert and his aide Gene, Sgt. O'Neal, and Charles Caiman. But of course, kudos DO have to be given to Jean Reno as Phillipe Roache, the collected, level-headed, and brave French Secret Service agent. He's essentially the kind of character that Roland Tembo from "The Lost World: Jurassic Park" was if you think about it.
Overall, I loved "Godzilla 1998" back then, and I still love it now, equally as much as "Godzilla 2014." A solid 8/10.