High-back or backless booster — which should I buy?

Across the reviewers we read, high-back boosters are generally favored for better belt routing and side-impact protection, especially in vehicles with low seatbacks or no headrest. Consumer Reports specifically noted that the Britax Skyline delivers far better belt fit in high-back mode than as a backless booster. Backless boosters like the Chicco GoFit and Graco TurboBooster LX are praised mainly for travel, carpools, and older/larger kids who already get good belt fit.