The most accurate simulators can measure plenty of data points, including clubhead speed, swing path, clubface angle, attack angle, tempo, ball spin rates, and much more. One great example is Flightscope's X3 launch monitor, which is capable of tracking over 50 metrics related to full swings and short game (putting & chipping). Cheaper models provide fewer data parameters and tend to be a tad less accurate than high-end systems (but still acceptable). The key is utilizing all the data to understand the causes of swing errors.