Everyone's taste is different. Here are my thoughts.
Pillars is one of my personal favorites. Absolutely loved the time period, the characters, the attention to detail. Couldnt wait to read the sequel (WWE) and was fairly disappointed. Seemed artificial and contrived compared to POTE.
I enjoyed Fall of Giants and Winters of the World. While I dont think they come close to matching Pillars in terms of the epic storyline, I did enjoy how Follett weaved together the lives of the five main families in the novel. To be fair, I am not as well read on early 20th century history compared to others so I enjoyed how Follett brought many of the major WW1 battles to life - the Battle of the Somme, etc. Could have done without the scenes involving Woodrow Wilson but it didnt ruin it for me either.
Cant wait to see Tims top 20.