We use scented paint always, only renting an ozone machine as a last resort. Usually after a smoker vacates, we do a full paint, seal floor, change carpets, and that does the trick. If the carpets don't need changed we clean them and then do the ozone.
The disadvantage of using an ozone machine is the down time. We can't afford to leave a unit vacant for two days to ozone treat it then air it back out. It is much faster to paint and seal, which can be done in less than a day.