Valerie D'Orazio has a brief comparison of Crisis on Infinite Earths versus Final Crisis. I must confess that I don't recall all the details of Crisis, but I do remember where I was when I read about Barry Allen's sacrifice in Issue 10 (on a Metro-North train heading north to Croton-on-Hudson, if you must know). Now I'm curious and want to check it out again to see if it still holds up. I remember it as being very melodramatic with lots of teeth-gnashing and hand-wringing, with a cast of thousands upon thousands.
Maybe my memory of it is colored by all the weird continuity that's happened since then. Stuff that made the last 20 years or so less fun to really enjoy.