For this playthrough, I did the SEBEC story route.
The way people talk about this game, I was expecting this game to feel a lot more crusty then it actually did for me. Outside of a really sudden difficulty spike near the end that caused me to stop and grind for a few hours and some pretty obvious exploits (you can spam megidola your way out of most battles), I think this holds up pretty well. I really liked the way you have to set your party's positioning on the grid. I was definitely disappointed when I booted up P2 and that was completely removed. Also, I'm not sure if this is an unpopular opinion but the demon negotiation in this game (and P2) might be my favorite way it's handled in the entire franchise. It feels so dynamic to have to match your party's personalities to the demons your trying to recruit (or rather get cards from in this case.)
As for the story, I think it's a pretty simple plotline but I think it's incredibly effective at what it's trying to tell. At least for the plotline I played. I can easily see myself coming back to this game since there's an entire separate campaign, the Snow Queen, to go through as well as just going through the SEBEC route again with different recruiteable party members. One playthrough won't take you long, so if you're even a little curious, I recommend giving the game a shot.
Also, I wasn't sure where to fit this in but to address discourse on the OST, I definitely got the immediate feeling after an hour of playing this wasn't the game's original soundtrack. What's on the PSP version isn't bad. They wanted to make it match P3 which is very far from a bad thing to sound like. It just doesn't work for the game in my opinion. There's a patch out there I'd recommend getting to change it back to ps1 ost. Ideally, if Atlus ever remembers this game exists and does a re-release they'll do the right thing and have both soundtracks available from options.