It's simple. I pay this card off every month to a zero balance. I get 2% cash back on everything I buy. I use this now instead of my debit card entirely, and my annual cash back is well over $500. I also used it when they offered a zero percent promo on a balance transfer, paid that off within the 15 month promo period, so again, zero cost to me.
If you complain about their high interest rate on balances, you're doing it wrong, but I understand not everyone can pay the balance off every mo. In that case, get a card with a very low interest rate.
My credit limit went from $1500 to $3000 to $7500 to $15500 to $20000. I've had the card for 4 yrs. Website is super easy to navigate, online payments are processed instantly, and I've had no issue with their call center resolving any problems. Overall, I am very satisfied.