WLL quality is pretty good, but obviously depends on your criteria and altitude.
Like most such sensors, it's a good idea to calibrate it to a good online estimate of your local eg QNH when setting up, but thereafter (and assuming you live not too far above sea level) then it should track ±1mb, probably a little better. Occasional checks and, if necessary, recalibration against a reference online QNH will give you a good feel for stability but users generally see good results.
