I always though C1 was a bit overrated. I saw it as inferior to American Life, Music, and especially Ray of Light. It's always slightly bothered me that it was held up as "her best" in certain quarters of the gay internet.
It has undeniable highs (Hung Up, Get Together, Sorry, Jump, Forbidden Love), but it's also got quite a lot of filler (I Love New York, How High, Push) relative to the run time.
It's too early to judge C2 and whether it stands up, but it's definitely more sonically interesting and confessional, which in itself makes it a more interesting proposition.