Other cards only let you get the bonus once. Citi lets you apply at least once every 62-64 days and get the bonus each time (as long as you satisfy the $750 spend within 4 months each time). Thus much more than 45k bonus possible within a year with Citi, while those cards that offer 45k that's 45k once and once only. Thus apples and oranges.

See the Citi "60 day" thread for much much more on this...