Finished the game tonight with 100% pickups. Final save time after the boss was 20:02, adding up the Wii log comes out to just over 33 1/2 hours play time. Odd how wide the gap got, but then again with Super Metroid on the VC the final save was roughly 60% of the total play time by the log, so I guess the Metroid games count it oddly (on top of losing time when you die and restart etc.).
Beat the final bosses on my 2nd try (though was borderline dead when I won). So Mogenar was indeed the only one that gave me any trouble at all.
Overall, it was a fantastic game. I'd give it a 9.5, with just a few minor nitpicks keeping it from getting a 10. Namely, control quirks (missles on down use of + and - buttons never got super comfortable and the game really needed a 180 quick turn as the turning was slow even on advanced), the above noted slow loads, and some occasionally distracting jaggies in the graphics.
But those are minor in the grand scheme of the game, which excelled in every other area. Controls (quirks above aside) where great, art design was fantastic, it was a long game than never got boring, great boss fights, great music etc. etc.
It also improved on the first two games for me in a couple of respects (above and beyond the superior controls), though the more hardcore among you probably count these as negatives.
1. It was easier, the first two (especially the second) were too hard for me. Nice to see variable difficulty from the start, with normal for sucky gamers like me, and veteran for the more skilled (and hyper after beating the game). That way everyone can enjoy the game. Nice to see it thrown in since pretty much every other FPS ever has difficulty options.
2. The chozo observatory was a great touch. I never got 100% in the other games as I don't have the patience to run around blindly searching every room. Being able to see where the items are allowed me to get 100% without wasting too much time.
Bravo Nintendo! Here's to hoping they keep up the excellence with Mario Galaxy!