Bannister actually received a lot of criticism for using pacers to break the barrier. Amateur officials argued that that's not what track was all about, it was about one runner trying to beat another. Earlier attempts actually had one pacer get lapped, having only run 2 laps when Bannister would come around for the bell - had he run sub-4 for that they would have not wanted to count it as the "first".
Many people liked Landy because he was always determined in running alone up front, believing that his strength would carry him thru. It was Chataway breathing down Landy's neck in Finland, something Landy wasn't used to, that pushed him that extra bit the last lap to run his 3:57.9.
Bannister was extra determined to beat Landy in their head-to-head "Miracle Mile" in Vancouver that year because he knew that if he didn't win, Landy would always be remembered as the faster man and the better racer. He had been determined to get to sub-4 first to redeem himself from the '52 Olympics in which he "failed" his country - now he didn't want losing to Landy to overshadow his feat of being the first to break the barrier.