Is it better to have a straight backspin or a straight forehand?

Determined by your personal physical fitness, playing style. If you are not strong enough because you are old or for other reasons, it's better to go for a straight rubber. Because although the reverse rubber can also be fast attack, but more for pulling the arc circle. The fact that you can use the reverse rubber to pull the arc requires a series of smooth and coordinated movements of the arms, waist and feet, and requires a lot of physical strength, so if you are young and have good power, it is recommended that you use the reverse rubber, and the arc is after all the mainstay of table tennis.