I beat the game. Took over 40 hours and I had to skip out on a few optional bosses because they were really too hard. By then I was lvl60 and my party was practically invincible in the final dungeon and all the final bosses were pushovers. So that should be a good indicator about how hard certain uber-bosses are.
If you bother to train up and do every single thing in the game, it would probably take 50 hours at most. If you rush through the game skipping all optional content (what a waste!) the game would probably take 30-35 hours to beat. The length is great because it's neither too short nor too long, and the worldview is great. The game is easy enough for beginners and there's tons to collect, customize and explore for more hardcore RPG players.
My initial impressions were that this game is very much a next-generation FFV style game, and that carries through all the way to the very end. From the setting, the characters, the gameplay, to the way sidequests and secrets are presented and scattered around the world, and the underlying game mechanics and so on, this is in every way a next generation FFV. Improvements like not having random encounters, and better scenario presentation make it feel like an upgraded experience as well. I really, really liked it.
As long as Sakaguchi is writing and designing the game, and the same team is behind it, I'll play any sequel they decide to make based on this. There's nothing generic about Blue Dragon. It may be a very oldschool traditional JRPG with a few modern ideas thrown in and really great next-generation graphics and animations, but the actual world design, events and places are anything but generic. By the end there should be plenty of memorable moments filled with charm and joy.