Asking whether to shoot straight vs slightly bent is like Ford vs Chevy. I shoot better straight armed. For me (and me only) shooting a straight arm is very easy to duplicate shot after shot. Slightly bent arm works for me also. BUT, after shooting several 3D targets (throwing in variables here like tiredness and stress levels), my bow arm can get tired. A tired bow arm with a slightly bent arm can lead to variances and rights/lefts and low/highs. Now I concentrate on the same grip feel, then bow arm straightness, release grip, and then back tension. But what works for one may not for the other.