I've had nothing but great experiences with lowestfare.com. The discounts are real, just check the twa website, then go to lowestfare.com. Same exact flights, 25-30% off.
Miles are always credited. No online bonus but saving a couple of hundred dollars is better than 1000 miles anyway.
One caution: you always get the way back of the bus for seat assignments. Rows 25+. call TWA direct as soon as you receive your tickets (they are sent UPS) and change them.
Charles