I finished Second Foundation by Isaac Asimov last night, the final book of the original Foundation Trilogy. I liked the second half more than the first, and overall, I think I preferred this book to its predecessor, but thought Foundation was the best of the three.
I still don't quite understand why people like them so much. They have an important trailblazing role in the genre, but the quality is just not there. It's a bit like saying Train Arriving at a Station is one of the best movies of all time. (Okay, maybe that's harsh.
A better comparison might be a classic silent movie, let's say Modern Times or Metropolis, and while they certainly have their advocates, most people won't get too much out of them now.)