RTD's have a much broader temperature range than thermistors. RTD's follow a linear resistance versus temperature profile, whereas thermistors follow a curve. RTD's find their greatest usage in HVAC and industrial applications. Thermistors occupy a broader range of the temperature sensing field, including medical, automotive, HVAC, and industrial markets. It's hard to put a number on it.
Drift increases exponentially with temperature and duration of exposure to elevated temperature.
Humidity and thermal shock also contribute to drift. RTD's RTD's can also experience a certain amount of drift. However, they are much less susceptible to drift due to exposure at elevated temperatures than thermistors are. Thermistors are available in point match and interchangeable varieties. However, a number of configurations are available with regard to tolerance and temperature range.