Fast and accurate link quality estimation is an important feature for wireless protocols such as routing, rate switching or handover. Existing signal strength based estimators tend to be fast but inaccurate while packet statistic based approaches are more accurate but require longer estimation times. We propose a new link quality estimation approach based on chip errors in symbols for direct sequence spread spectrum transceivers. The new link quality estimator is evaluated experimentally with software defined radios on IEEE 802.15.4 for different link conditions, including multi-path and mobile scenarios. We show that our chip error based link quality estimator performs more accurately than received signal strength based estimators and much faster than the packet statistic based estimators with comparable accuracy. With our approach, only a single packet, or even a fraction of a packet (e.g., only a few symbols), is necessary to obtain similar performance as state-of-the-art approaches that require at least 10 packets.