it sure seems like a deal too me. just be being approved, you get an instant $200 in bonus rebates, and you get an additional $50. you get this added to your account after your first purchase balance transfer or when you use their check. here are the terms and conditions, which doesn't look shady at all.
*You will receive $200 in bonus rebates which can be redeemed for a $250 check. Please allow 6 to 8 weeks after your first purchase for bonus rebates to post to your account. First purchase includes purchases, balance transfers, or any checks that are used to access your account. To qualify for bonus rebates, account must be open and not in default at the time of fulfillment. The bonus offer is valid only for first-time cardmembers with new accounts. Only one bonus per account. Existing cardmembers/accounts are not eligible for the bonus offer. Learn more about rates, fees, and other cost information by reviewing Pricing & Terms.
For a card like this, i would only use it to purchase grocery's, gas, and fast food, where i would maximize the 3% and paying off those bills every month in full isn't so tough.
free $250 for getting an account sounds like a deal to me.