I don't hate P4 by any means, I just feel that it is weak in comparison to the other games. (I haven't played P1 so I cannot speak for that one)
I like the story, setting, and Adachi, Nanako and Naoto are some of my favorite characters in the entire series, but...
I don't like how the game is handled post November. Particularly the arc with Adachi, but I will keep my opinion to myself as that is another can of worms.
I didn't feel as sympathetic towards the party as I did in other games. I found Yosuke and Teddie to be very annoying characters with few redeeming qualities, and Yukiko and Rise's social links are handled poorly and go in a full circle. Nothing really changes. I really like Chie, Naoto and Kanji though.
Another part that annoys me about the game is that it tries to manipulate you towards a bad. I'm talking about the scene in the hospital of course.
Overall, I do really love P4 but several aspects drop it down in comparison to the other games. I'm not ever saying I hate it.
Adachi, Kanji, Naoto, Ayane and Nanako are treasures.